Discovery of a Marine Bacterium Producing 4-Hydroxybenzoate and Its Alkyl Esters, Parabens

Chemically synthesized 4-hydroxybenzoate (4HBA) is widely used in the chemical and electrical industries as a material for producing polymers such as those of the liquid crystal type. Its alkyl esters, called parabens, have been the most widely used preservatives by the food and cosmetic industries. We report here for the first time a microorganism, a marine bacterium, which biosynthesizes these petrochemical products. The marine bacterial strain, A4B-17, which was found to belong to the genus Microbulbifer on the basis of its rRNA and gyrB sequences, was isolated from an ascidian in the coastal waters of Palau. Strain A4B-17 was, surprisingly, found to produce 10 mg/liter of 4HBA, together with its butyl (24 mg/liter), heptyl (0.4 mg/liter), and nonyl (6 mg/liter) esters. We therefore characterized 23 other marine bacteria belonging to the genus Microbulbifer, which our institute had previously isolated from various marine environments, and found that these bacteria also produced 4HBA, although with low production levels (less than one-fifth of that produced by A4B-17). We also show that the alkyl esters of 4HBA produced by strain A4B-17 were effective in preventing the growth of yeasts, molds, and gram-positive bacteria.     

Thioredoxin-binding protein-2 (TBP-2): its potential roles in the aging process

Thioredoxin (TRX) binding protein-2 (TBP-2), a negative regulator of TRX, is involved in intracellular redox regulation and cellular growth. The expression of TBP-2 is frequently lost in tumor cell lines and tissues, whereas the ectopic expression of TBP-2 suppresses cellular proliferation along with cell cycle arrest at the G1 phase. TBP-2 was also reported to be a cellular senescence-associated gene. Besides the retardation of cellular growth, the reduction of white adipose, and alteration of the energy pathway are involved in several features of the aging process. We have generated TBP-2 genetically modified mice and found that TBP-2 is closely linked to lipid metabolism. Indeed, TBP-2 has been suggesting to be related to familial combined hyperlipidemia analyzed by a spontaneous mutant mouse strain. As lipid metabolism is one of the most primitive sources of energy production, we discussed the possible roles of TBP-2 in the regulation of energy utilization connected to the aging process.     

Intravesical administration of γδ T cells successfully prevents the growth of bladder cancer in the murine model

Background  Superficial bladder cancers are usually managed with transurethral resection followed by the intravesical administration of Bacillus Calmette-Guerin which requires major histocompatibility complex (MHC) class I expression on cancer cells. Since cancer cells often loose MHC expression, a novel immunotherapy such as MHC-unrestricted γδ T cell therapy is desired. Objective  To clarify the relationship between the expression of MHC class I and clinicopathological features in bladder cancer patients, and investigate the effects of the administration of intravesical γδ T cells on bladder cancer. Methods  Samples from 123 patients who had undergone either transurethral resection or radical cystectomies were examined for MHC expression and the relationship between this and the clinicopathological features was analyzed statistically. The in vitro and in vivo effects of γδ T cells expanded by zoledronic acid (ZOL) against several types of cancer cell line and an orthotopic bladder cancer murine model which was pretreated with ZOL were investigated. Results  MHC-diminished superficial bladder cancer was significantly more progressive than MHC-conservative bladder cancer (P = 0.047). In addition, there was a significant association between diminished MHC expression and poor disease free survival (P = 0.041) and overall survival (P = 0.018) after radical cystectomy. In vitro, all of the cell lines pretreated with 5-μM ZOL showed a marked increase in sensitivity to lysis by γδ T cells. Moreover, intravesical administration of γδ T cells with 5-μM ZOL significantly demonstrated antitumor activity against bladder cancer cells in the orthotopic murine model (P < 0.001), resulting in prolonged survival. Conclusion  The present murine model provides a potentially interesting option to develop immunotherapy using γδ T cells for bladder cancer in human. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. T. Yuasa and K. Sato contributed equally to the study.     

Kidney regeneration through nephron neogenesis in medaka

Although renal regeneration is limited to repair of the proximal tubule in mammals, some bony fish are capable of renal regeneration through nephron neogenesis in the event of renal injury. We previously reported that nephron development in the medaka mesonephros is characterized by four histologically distinct stages, generally referred to as condensed mesenchyme, nephrogenic body, relatively small nephron, and the mature nephron. Developing nephrons are positive for wt1 expression during the first three of these stages. In the present study, we examined the regenerative response to renal injury, artificially induced by the administration of sublethal amounts of gentamicin in adult medaka. Similar to previous reports in other animals, the renal tubular epithelium and the glomerulus of the medaka kidney exhibited severe damage after exposure to this agent. However, kidneys showed substantial recovery after gentamicin administration, and a significant number of developing nephrons appeared 14 days after gentamicin administration (P < 0.01). Similarly, the expression of wt1 in developing nephrons also indicated the early stages of nephrogenesis. These findings show that medaka has the ability to regenerate kidney through nephron neogenesis during adulthood and that wt1 is a suitable marker for detecting nephrogenesis.     

The 3′-Phosphoadenosine 5′-Phosphosulfate Transporters,PAPST1 and 2, Contribute to the Maintenance and Differentiation of Mouse Embryonic Stem Cells

Recently, we have identified two 3′-phosphoadenosine 5′-phosphosulfate (PAPS) transporters (PAPST1 and PAPST2), which contribute to PAPS transport into the Golgi, in both human and Drosophila. Mutation and RNA interference (RNAi) of the Drosophila PAPST have shown the importance of PAPST-dependent sulfation of carbohydrates and proteins during development. However, the functional roles of PAPST in mammals are largely unknown. Here, we investigated whether PAPST-dependent sulfation is involved in regulating signaling pathways required for the maintenance of mouse embryonic stem cells (mESCs), differentiation into the three germ layers, and neurogenesis. By using a yeast expression system, mouse PAPST1 and PAPST2 proteins were shown to have PAPS transport activity with an apparent K_m value of 1.54 µM or 1.49 µM, respectively. RNAi-mediated knockdown of each PAPST induced the reduction of chondroitin sulfate (CS) chain sulfation as well as heparan sulfate (HS) chain sulfation, and inhibited mESC self-renewal due to defects in several signaling pathways. However, we suggest that these effects were due to reduced HS, not CS, chain sulfation, because knockdown of mouse N-deacetylase/N-sulfotransferase, which catalyzes the first step of HS sulfation, in mESCs gave similar results to those observed in PAPST-knockdown mESCs, but depletion of CS chains did not. On the other hand, during embryoid body formation, PAPST-knockdown mESCs exhibited abnormal differentiation, in particular neurogenesis was promoted, presumably due to the observed defects in BMP, FGF and Wnt signaling. The latter were reduced as a result of the reduction in both HS and CS chain sulfation. We propose that PAPST-dependent sulfation of HS or CS chains, which is regulated developmentally, regulates the extrinsic signaling required for the maintenance and normal differentiation of mESCs.     

Suppression of histone deacetylase 3 (HDAC3) enhances apoptosis induced by paclitaxel in human maxillary cancer cells in vitro and in vivo

Inclusion of chemotherapeutic drugs in treatment of patients with newly diagnosed head and neck cancer has improved response rates and prolonged median survival. Nevertheless, most patients with advanced head and neck cancer are destined to relapse and to develop resistance to initially used drugs such as paclitaxel. Consequently, it has been more important in cancer therapy to determine the molecular mechanisms that are related to cell-killing effects of anti-cancer agents or cancer resistance against them. Consequently, we examined whether abrogation of histone deacetylase 3 (HDAC3) expression by anti-sense oligonucleotides (ASOs) potentiates the efficacy of paclitaxel in human maxillary cancer IMC-3 cells. Here, we showed that paclitaxel-induced apoptosis was enhanced significantly by addition of ASOs for HDAC3 in cultured cells. Furthermore, paclitaxel-induced apoptosis in IMC-3 tumors transplanted in nude mice was enhanced significantly by administration of ASOs for HDAC3, thereby suppressing tumor growth. We provide new evidence that HDAC3 is a novel molecular target whose inactivation can potentiate the efficacy of anti-cancer drugs disrupting microtubules such as paclitaxel.     

Impaired flow-dependent control of vascular tone and remodeling in P2X4-deficient mice

The structure and function of blood vessels adapt to environmental changes such as physical development and exercise. This phenomenon is based on the ability of the endothelial cells to sense and respond to blood flow; however, the underlying mechanisms remain unclear. Here we show that the ATP-gated P2X4 ion channel, expressed on endothelial cells and encoded by P2rx4 in mice, has a key role in the response of endothelial cells to changes in blood flow. P2rx4(-/-) mice do not have normal endothelial cell responses to flow, such as influx of Ca(2+) and subsequent production of the potent vasodilator nitric oxide (NO). Additionally, vessel dilation induced by acute increases in blood flow is markedly suppressed in P2rx4(-/-) mice. Furthermore, P2rx4(-/-) mice have higher blood pressure and excrete smaller amounts of NO products in their urine than do wild-type mice. Moreover, no adaptive vascular remodeling, that is, a decrease in vessel size in response to a chronic decrease in blood flow, was observed in P2rx4(-/-) mice. Thus, endothelial P2X4 channels are crucial to flow-sensitive mechanisms that regulate blood pressure and vascular remodeling.     

Differential inhibition of HMG-CoA synthase and pancreatic lipase by the specific chiral isomers of beta-lactone DU-6622

A synthetic beta-lactone trans-DU-6622 (3-hydroxy-2-(hydroxymethyl)-5-[7-(methylcarbonyl)-naphthalen++ +-1-yl]pentanoic acid 1,3-lactone, a mixture of (2R, 3R)- and (2S, 3S)-beta-lactones) was found to inhibit HMG-CoA synthase (IC(50): 0. 15 microM) and pancreatic lipase (IC(50): 120 microM). The effects of the optically pure DU-6622 isomers on the two enzymes were compared. The (2R, 3R)-isomer was shown to be a highly specific inhibitor of HMG-CoA synthase (IC(50): 0.098 microM vs 270 microM for pancreatic lipase), while the (2S, 3S)-isomer markedly increased the specificity of lipase inhibition (IC(50): 27 microM vs 31 microM for HMG-CoA synthase). Furthermore, the (2R, 3R)-isomer strongly inhibited the binding of [(14)C]hymeglusin to HMG-CoA synthase, indicating that the isomer was bound to the same site of the synthase as hymeglusin. The (2R, 3R)-beta-lactone is responsible for the specific inhibition of HMG-CoA synthase, while the (2S, 3S)-beta-lactone is responsible for the inhibition of pancreatic lipase.