Depression-like Behavior Induced by Repeated Administration of Dexamethasone to Lipopolysaccharide-inflamed Mice.

BACKGROUND: Over the years, animal models of depression have been developed by loading chronic stress, inducing neuroinflammation, or administering drugs that induce depression; however, these results have poor reproducibility. Therefore, it is necessary to develop animal models that exhibit definitive symptoms of depression for studies on potential therapeutics. OBJECTIVE: This study was aimed at investigating depression-like symptoms and their pathogenesis in lipopolysaccharide (LPS)-inflamed mice treated with dexamethasone (DEX). METHODS: Male ICR mice were injected with LPS, followed by injection with DEX a day later and each day for 6 consecutive days. Depression-like behavior, expression of the glial markers glial fibrillary acidic protein (GFAP) and ionized calcium-binding adapter molecule 1 (Iba1), and the number of the immature neuronal marker doublecortin (DCX)-positive cells were assessed using tail-suspension test (TST), forced swim test (FST), western blot analysis, and immunohistochemical analysis. RESULTS: Mice in the LPS+DEX group had significantly longer immobility time in the TST and FST than did those in the LPS- or DEX-only and control groups on day 7 post-LPS administration. GFAP and Iba1 expression was significantly elevated in the hippocampus of mice in the LPS group than in those of mice in the control group. Moreover, a significantly lower number of DCX-positive cells was observed in the hippocampal dentate gyrus of mice in the LPS+DEX group compared with that in mice in the LPS- or DEX-only and control groups on day 7 after LPS administration. CONCLUSION: Repeated DEX administration to LPS-inflamed mice may induce definitive depression-like symptoms by decreasing the number of immature neurons in the hippocampal dentate gyrus. This novel mouse model of depression was produced by repeated administration of steroids to inflamed mice.

Elucidation of host diversity of the VanD-carrying genomic islands in enterococci and anaerobes.

BACKGROUND: VanD is a rare type of vancomycin resistance worldwide. However, the host diversity of the vanD gene cluster and the structural similarity of their genomic islands are not well understood. METHODS: Three VanD-type Enterococcus faecium strains (AA620, AA622 and AA624) isolated from a Japanese patient who underwent vancomycin treatment in 2017 were analysed. This study utilized WGS analysis to characterize the three VanD-type E. faecium strains and describes the diversity of hosts possessing VanD-carrying genomic islands. RESULTS: The three isolates exhibited variable MICs of vancomycin. In the relatively vancomycin-resistant AA620, mutations were identified in vanSD and ddl. The strains AA622 and AA624 had intact ddl and harboured two vanD gene clusters. qRT-PCR results revealed the ddl mutation to be a factor affecting the high vancomycin resistance range of AA620. WGS data showed the 155 kb and 185 kb genomic islands harbouring the vanD gene cluster inserted in the coding region of the lysS gene, located in the chromosome in AA620 and AA622/624, respectively. Comparing the VanD-carrying genomic islands to available sequences of other enterococci and enteric anaerobes revealed how the genomic islands of these organisms isolated worldwide shared similar core genes and backbones. These anaerobes belonged to various genera within the order Eubacteriales. The phylogenetic cluster of the genomic island core genome alignment did not correlate with the host-species lineage, indicating horizontal gene transfer in the gut microbiota. CONCLUSIONS: By horizontal gene transfer, various bacteria forming the gut microbiota maintain VanD-carrying genomic islands.

Embryonic regulation of the mouse erythropoietic niche and its clinical application.

Erythropoiesis has classically been described as occurring in two waves: first primitive and then definitive erythropoiesis. In the mouse embryo, definitive erythropoiesis begins in the yolk sac and then shifts to the liver, spleen, and bone marrow. The fetal liver serves as the primary organ for erythroid cell expansion and maturation at mid-gestation and its mechanisms have been well investigated with special attention to niche cells expressing cytokines such as SCF, TPO and IGF2. Previously, our group reported that DLK1(+) hepatoblasts support fetal liver hematopoiesis, particularly erythropoiesis, through EPO, SCF and matrix secretion. Loss of DLK1(+) hepatoblasts in Map2k4(-/-) mouse embryos resulted in decreased numbers of hematopoietic cells in the fetal liver. When sorted DLK1(+) hepatoblasts were further analyzed by microarray, several genes encoding proteinases and peptidases were highly expressed in DLK1(+) hepatoblasts. Based on the hypothesis that high molecular weight proteins are digested into small peptides that may regulate hematopoiesis, we screened out peptides, and identified KS-13 (PCT/JP2010/067011). Both KS-13 and modified KS-13, known as SL-13R, proliferate and increase the number of hematopoietic stem/progenitors from human cord blood cells in vitro. We hereby present our findings on the extrinsic regulation of embryonic erythropoiesis with special attention to niche cells, identification of niche-derived peptides, and implications for future hematotherapy.

Prospects for Harmonizing Regulatory Science Programs in Europe, Japan, and the United States to Advance Regenerative Medicine.

BACKGROUND: Regenerative medicine (RM) is a game-changing technology with the potential to repair damaged tissues and organs, but its introduction into the clinic is complicated by the fact that Europe, Japan, and the United States are struggling to make appropriate regulatory decisions about advanced technologies that are highly promising but also uncertain and potentially risky. They have adopted the new approach of regulatory science (RS), applying science-based approaches and standards to support regulatory decision making, to address the challenge. METHODS: Is RS the right approach for harmonizing the regulatory mechanisms needed to integrate RM into the mainstream of the development continuum for medical products? If so, what are the prospects for harmonization? We examine the current state of the art for RM and RS in the 3 major drug development regions to answer these questions. RESULTS: Among the practical obstacles to harmonization is the fact that the 3 regions represent different legal jurisdictions and health care systems, with disparate regulatory and reimbursement requirements. However, the regulatory regimes are not without commonalities. Thus, it is not the practical differences that should be debated but rather how best to enhance collaboration. CONCLUSIONS: Just as consistent and predictable regulatory support founded on common principles in regulatory science provide the confidence and certainty required to bolster investment in regenerative medicine, harmonization is essential to building that framework on a global scale.

Apoptosis-inducing Factor, Mitochondrion-associated 2, Regulates Klf1 in a Mouse Erythroleukemia Cell Line.

BACKGROUND/AIM: Apoptosis-inducing factor, mitochondrion-associated 2 (Aifm2), is a DNA-binding oxoreductase protein that promotes apoptosis. To assess its potential role in erythropoiesis we analyzed the effects of Aifm2 loss-of-function in the murine erythroleukemia line (MEL). MATERIALS AND METHODS: MEL cells were transfected with siRNA targeting Aifm2 for 24 h and evaluated by cell counting, flow cytometry with annexin V and PI staining and gene expression analysis. RESULTS: Aifm2 knockdown did not affect the apoptotic status of MEL cells. However, Aifm2 knockdown significantly increased expression of the erythropoietic transcription factor Klf1 (2.9±0.2-fold, p<0.05) and decreased α- and ß-globin expression (0.6±0.2-fold, p<0.05 and 0.5±0.2-fold, p<0.01). CONCLUSION: Aifm2 may function in differentiation of erythroid MEL cells in vitro.

High-throughput screening of low molecular weight NS3-NS4A protease inhibitors using a fluorescence resonance energy transfer substrate.

Hepatitis C virus (HCV) NS3-NS4A protease is an attractive target for anti-HCV agents because of its important role in replication. An optimized fluorescence resonance energy transfer (FRET) substrate for NS3-NS4A protease, based on the sequence of the NS5A-5B cleavage site, was designed and synthesized. High-throughput screening of in-house compound libraries was performed using a FRET substrate FS10 (MOCAcDKIVPC-SMSYK-Dnp) and MBP-NS3-NS4A fusion protein. Several hit compounds were found, including YZ-9577 (2-oxido-1,2,5-oxadiazole-3,4-diyl) bis (phenylmethanone) with potent inhibitory activity (IC50=1.6 microM) and good selectivity against other human serine proteases.

YM-53403, a unique anti-respiratory syncytial virus agent with a novel mechanism of action.

We performed a large-scale random screening of an in-house chemical library based on the inhibition of respiratory syncytial virus (RSV)-induced cytopathic effect on HeLa (human cervical carcinoma) cells, and found a novel and specific anti-RSV agent, 6-{4-[(biphenyl-2-ylcarbonyl) amino]benzoyl}-N-cyclopropyl-5,6-dihydro-4H-thieno[3,2-d][1]benzazepine-2-carboxamide (YM-53403). YM-53403 potently inhibited the replication of RSV strains belonging to both A and B subgroups, but not influenza A virus, measles virus, or herpes simplex virus type 1. A plaque reduction assay was used to determine the 50% effective concentration (EC(50)) value for YM-53403. The value, 0.20 microM, was about 100-fold more potent than ribavirin. The result of a time-dependent drug addition test showed that YM-53403 inhibited the life cycle of RSV at around 8h post-infection, suggesting an inhibitory effect on early transcription and/or replication of the RSV genome. Consistent with this result, two YM-53403-resistant viruses have a single point mutation (Y1631H) in the L protein which is a RNA polymerase for both the transcription and replication of the RSV genome. YM-53403 is an attractive compound for the treatment of RSV infection because of its highly potent anti-RSV activity and the new mode of action, which differs from that of currently reported antiviral agents.

Functions of a chitosan-orotic acid salt in the gastrointestinal tract.

A chitosan (CS)-orotic acid salt (CS-OT) was prepared, and the release of orotic acid (OT) from CS-OT as well as the adsorption of bile acids by CS-OT was investigated in vitro. The amount of OT released from CS-OT was about 2-2.7 micromol/mg CS-OT and this changed depending on the species of CS. CS-OT also adsorbed bile acids and the amount increased incrementally according to the number of amino group contained in CS. Furthermore, CS-OT was given to rats as feed in order to investigate the influence on serum cholesterol levels. A decrease in serum cholesterol levels was observed in the group, which was fed a diet containing CS-OT or CS for 1-2 weeks, but no differences in body weight changes were recognized. Therefore, CS-OT may be applied to treating hyperlipidemia.