Spirotoamides A and B, novel 6,6-spiroacetal polyketides isolated from a microbial metabolite fraction library

Two new 6,6-spiroacetal polyketides, spirotoamides A (1) and B (2), were isolated from a microbial metabolite fraction library of Streptomyces griseochromogenes JC82-1223 by screening of structurally unique compounds based on a search of spectral database. The fraction library was constructed using a systematic separation method to efficiently discover new metabolites from microbial sources such as actinomycetes and fungi. The structures of 1 and 2 were elucidated by 2D-NMR and mass spectrometric measurements. They belong to a class of polyketides, and contain a 6,6-spiroacetal core structure and a carboxamide group. The biosynthetic pathway of 1 and 2 is discussed in the text.     

Maternal GABAergic and GnRH/corazonin pathway modulates egg diapause phenotype of the silkworm Bombyx mori

Diapause represents a major developmental switch in insects and is a seasonal adaptation that evolved as a specific subtype of dormancy in most insect species to ensure survival under unfavorable environmental conditions and synchronize populations. However, the hierarchical relationship of the molecular mechanisms involved in the perception of environmental signals to integration in morphological, physiological, behavioral, and reproductive responses remains unclear. In the bivoltine strain of the silkworm Bombyx mori, embryonic diapause is induced transgenerationally as a maternal effect. Progeny diapause is determined by the environmental temperature during embryonic development of the mother. Here, we show that the hierarchical pathway consists of a γ-aminobutyric acid (GABA)ergic and corazonin signaling system modulating progeny diapause induction via diapause hormone release, which may be finely tuned by the temperature-dependent expression of plasma membrane GABA transporter. Furthermore, this signaling pathway possesses similar features to the gonadotropin-releasing hormone (GnRH) signaling system for seasonal reproductive plasticity in vertebrates.

To ensure survival under unfavorable environmental conditions and synchronize populations, most insect species enter diapause, which is a seasonal adaptation that evolved as a specific subtype of dormancy (1, 2). Diapause is not a passive response to changing conditions but rather an actively induced state that precedes adverse natural situations. Therefore, this diapause phenotype is accompanied by changes in energy metabolism or storage to improve cold/stress tolerance in later life stages, or progeny via reproductive switch (3). Although it has been generally suggested that brain/neuroendocrine systems are associated with this seasonal reproductive plasticity in both vertebrates and invertebrates (3, 4), the hierarchical relationship of the molecular mechanisms involved in the perception of environmental signals to integration into morphological, physiological, behavioral, and reproductive responses, known as the diapause syndrome, remains unclear (3).The silkworm Bombyx mori is a typical insect that arrests normal development during early embryogenesis, which is accompanied by metabolic changes in diapause (5, 6). The development of diapause-destined embryos is arrested during the G2 cell cycle stage immediately after the formation of the cephalic lobe and telson and sequential segmentation of the mesoderm (7). The bivoltine strain of B. mori has two generations per year, and progeny diapause is transgenerationally induced as a maternal effect and is determined by the environmental temperature, photoperiod, and nutrient conditions during embryonic and larval development of the mother (5, 6). The temperature signal during the mother’s embryonic development predominantly affects diapause determination, even if silkworms of the bivoltine Kosetsu strain are exposed to all cases of photoperiods during embryonic and larval development. In the Kosetsu strain, when eggs are incubated at 25 °C under continuous darkness, the resultant female moths (25DD) lay diapause eggs in almost all cases. In contrast, incubation of eggs at 15 °C in dark condition results in moths (15DD) that lay nondiapause eggs in almost all cases (6).Embryonic diapause is induced by the diapause hormone (DH) signaling pathway, which consists of highly sensitive and specific interactions between a neuropeptide, DH, and DH receptor (DHR) (6, 8). DH is exclusively synthesized in seven pairs of neurosecretory cells (DH-PBAN–producing neurosecretory cells [DHPCs]) located within the subesophageal ganglion (SG) in the mother’s generation (6). DH is released into the hemolymph during pupal–adult development and acts on the DHR, which belongs to the G protein-coupled receptors (GPCRs) (9). DH levels in the hemolymph are higher in the 25DD than 15DD pupae in the middle of pupal–adult development when the developing ovaries are sensitive to DH (6). Furthermore, the embryonic Bombyx TRPA1 ortholog (BmTRPA1) acts as a thermosensitive channel that is activated at temperatures above ∼21 °C and affects diapause induction through DH release (10). However, there remain questions about the thermal information that is received by BmTRPA1 and linked to DH signaling to induce diapause.From the 1950s, it has been suggested that the DH release was controlled by signals derived from certain region(s) in the brain based on surgical experiments, such as midsagittal bisection or transection (11–13). Especially, the operation in nondiapause producers changed them to diapause producers while transection of the protocerebrum had no effect on the diapause producers. These surgical results suggested the involvement of the protocerebrum in the inhibitory control of DH secretion (12, 14). Furthermore, the accumulation of the ovarian 3-hydroxykynurenine (3-OHK) pigment that accompanies the diapause syndrome was affected by injection with γ-aminobutyric acid (GABA) and the plant alkaloid picrotoxin (PTX), which is a widely used ionotropic GABA and glycine receptor antagonist (15, 16), and the selective ionotropic GABA receptor (GABAR) antagonist bicuculline. This suggests that a GABAergic neurotransmission via ionotropic GABAR is involved in DH secretion, which may be active in nondiapause producers but inactive in diapause producers throughout the pupal–adult development (14, 17). In general, ionotropic GABAR is composed of homo- or hetero-pentameric subunits. All known GABAR subunits display a similar structural scheme, with a large N-terminal extracellular domain involved in the formation of a ligand-binding pocket and a pore domain made of four transmembrane alpha-helices (TM1–TM4) (16, 18). Four homologous sequences of the ionotropic GABAR subunit genes were identified as RDL, LCCH3, GRD, and a GRD-like sequence named 8916 in various insects (19). However, the in vivo physiological roles of both signals derived from the brain and the GABAergic pathway in diapause induction have not been previously investigated.Corazonin (Crz) is an undecapeptide neurohormone sharing a highly conserved amino acid (a.a.) sequence across insect lineages and is involved in different physiological functions, such as heart contraction (20), stress response (21, 22), various metabolic activities (23–25), female fecundity (26), melanization of locust cuticles (27), regulation of ecdysis (28, 29), and control of caste identity (30). Moreover, Crz belongs to the gonadotropin-releasing hormone (GnRH) superfamily alongside adipokinetic hormone (AKH) and AKH/Crz-related peptide (ACP). Duplicates of an ancestral GnRH/Crz signaling system occurred in a common ancestor of protostomes and deuterostomes through coevolution of the ligand receptor (31, 32).Herein, we demonstrated that the hierarchical pathway consists of a GABAergic and Crz signaling system modulating progeny diapause induction by acting on DH release. We propose that the PTX-sensitive GABAergic signal may act to chronically suppress Crz release in dorsolateral Crz neurons (under nondiapause conditions) and that diapause conditions (or PTX injection) inhibits GABAergic signaling, resulting in accelerated Crz release, which in turn induces DH release. GABA signaling may be finely tuned by the temperature-dependent expression of the plasma membrane GABA transporter (GAT), which differs between the 25DD and 15DD conditions. Furthermore, this signaling pathway possesses similar features to the GnRH signaling system with respect to seasonal reproductive plasticity in vertebrates.     

Primary esophageal mucosa‐associated lymphoid tissue lymphoma treated by endoscopic submucosal dissection

Primary esophageal mucosa‐associated lymphoid tissue (MALT) lymphoma is rare. There have been few reports about early primary esophageal MALT lymphoma being treated endoscopically. The clinical profile of primary esophageal MALT lymphoma is currently unclear, so it is important to accumulate more information about early esophageal MALT lymphoma. To achieve early detection of esophageal MALT lymphoma, we need more accurate knowledge and information about the macroscopic and morphological features of this tumor. Endoscopic resection is one of the most effective treatments. With respect to the lateral andvertical margins of the resected specimen, endoscopic submucosal dissection (ESD) may be superior to endoscopic mucosal resection for treating early esophageal MALT lymphoma. Here we report the macroscopic appearance of the tumor which is the first successful case of ESD for early esophageal MALT lymphoma.     

Prognostic usefulness of serum uric acid after acute myocardial infarction (the Japanese Acute Coronary Syndrome Study)

Serum uric acid (UA) levels reflect circulating xanthine oxidase activity and oxidative stress production. Hyperuricemia has been identified in patients who have congestive heart failure and is a marker of poor prognosis in such patients. We investigated the relation between serum UA levels and Killip's classification suggestive of the severity of heart failure and whether hyperuricemia influences mortality of patients who have acute myocardial infarction (AMI). Using the Japanese Acute Coronary Syndrome Study database, we evaluated 1,124 consecutive patients who were hospitalized within 48 hours of onset of symptoms of AMI from January to December 2002. There was a close relation between serum UA concentration and Killip's classification. Patients who developed short-term adverse events had high UA concentrations. Serum UA levels, Killip's class, age, and peak creatine phosphokinase level were significant predictors of long-term mortality. The hazard ratio for patients in the highest quartile of UA was 3.7 compared with those in the lowest quartile for death after AMI after adjustment for independent factors that were related to mortality. The combination of the best UA cutoff (447 micromol/L) for predicting survival based on receiver-operating characteristics analysis and Killip's class significantly predicted the prognosis of acute and long-term AMI-related complications. In conclusion, our results suggest that hyperuricemia after AMI is associated with the development of heart failure. Serum UA level is a suitable marker for predicting AMI-related future adverse events, and the combination of Killip's class and serum UA level after AMI is a good predictor of mortality in patients who have AMI.     

Involvement of aldosterone and mineralocorticoid receptors in rat mesangial cell proliferation and deformability

We demonstrated recently that chronic administration of aldosterone to rats induces glomerular mesangial injury and activates mitogen-activated protein kinases including extracellular signal-regulated kinases 1/2 (ERK1/2). We also observed that the aldosterone-induced mesangial injury and ERK1/2 activation were prevented by treatment with a selective mineralocorticoid receptor (MR) antagonist, eplerenone, suggesting that the glomerular mesangium is a potential target for injuries induced by aldosterone via activation of MR. In the present study, we investigated whether MR is expressed in cultured rat mesangial cells (RMCs) and involved in aldosterone-induced RMC injury. MR expression and localization were evaluated by Western blotting analysis and fluorolabeling methods. Cell proliferation and micromechanical properties were determined by [3H]-thymidine uptake measurements and a nanoindentation technique using an atomic force microscope cantilever, respectively. ERK1/2 activity was measured by Western blotting analysis with an anti-phospho-ERK1/2 antibody. Protein expression and immunostaining revealed that MR was abundant in the cytoplasm of RMCs. Aldosterone (1 to 100 nmol/L) dose-dependently activated ERK1/2 in RMCs with a peak at 10 minutes. Pretreatment with eplerenone (10 micromol/L) significantly attenuated aldosterone-induced ERK1/2 phosphorylation. Aldosterone (100 nmol/L) treatment for 30 hours increased [3H]-thymidine incorporation and decreased the elastic modulus, indicating cellular proliferative and deforming effects of aldosterone, respectively. These aldosterone-induced changes in cellular characteristics were prevented by pretreatment with eplerenone or an ERK (MEK) inhibitor, PD988059 (100 micromol/L). The results indicate that aldosterone directly induces RMC proliferation and deformability through MR and ERK1/2 activation, which may contribute to the pathogenesis of glomerular mesangial injury.     

Association of des-γ-carboxy prothrombin production and Sonazoid-enhanced ultrasound findings in hepatocellular carcinomas of different histologic grades

Purpose

We previously reported that hepatocellular carcinoma (HCC) changes to a phenotype producing des-γ-carboxy prothrombin (DCP) during epithelial mesenchymal transition (EMT) in vitro. To confirm this change in vivo, we evaluated the association between DCP production and HCC hemodynamics in patients undergoing resection as EMT and hemodynamic changes are closely associated with each other.

Methods

We evaluated HCC hemodynamics by employing Sonazoid-enhanced ultrasound (SEUS) before surgical resection, and sought associations with histological grade and immunohistochemical staining of DCP in 19 areas from 11 patients.

Results

In 10 HCC areas showing early washout (3 min ≥) using SEUS, three areas corresponded to poorly differentiated HCC and the remaining seven areas corresponded to moderately differentiated HCC, and positive DCP staining was observed in only two of the seven moderately differentiated HCC areas, whereas no staining was observed in poorly differentiated HCC areas. Six HCC areas showing intermediate washout (3–10 min) using SEUS were moderately differentiated, of which five demonstrated positive DCP staining (83.3%, 5/6). However, all HCC areas without enhancement in the arterial phase were well-differentiated and did not show DCP staining.

Conclusion

Our preliminary findings suggest that HCC hemodynamics evaluated by SEUS are associated with histological grade and/or DCP production.

     

Results and DVH analysis of late rectal bleeding in patients treated with 3D-CRT or IMRT for localized prostate cancer

In patients undergoing radiotherapy for localized prostate cancer, dose–volume histograms and clinical variables were examined to search for correlations between radiation treatment planning parameters and late rectal bleeding. We analyzed 129 patients with localized prostate cancer who were managed from 2002 to 2010 at our institution. They were treated with 3D conformal radiation therapy (3D-CRT, 70 Gy/35 fractions, 55 patients) or intensity-modulated radiation therapy (IMRT, 76 Gy/38 fractions, 74 patients). All radiation treatment plans were retrospectively reconstructed, dose–volume histograms of the rectum were generated, and the doses delivered to the rectum were calculated. Time to rectal bleeding ranged from 9–53 months, with a median of 18.7 months. Of the 129 patients, 33 patients had Grade 1 bleeding and were treated with steroid suppositories, while 25 patients with Grade 2 bleeding received argon plasma laser coagulation therapy (APC). Three patients with Grade 3 bleeding required both APC and blood transfusion. The 5-year incidence rate of Grade 2 or 3 rectal bleeding was 21.8% for the 3D-CRT group and 21.6% for the IMRT group. Univariate analysis showed significant differences in the average values from V65 to V10 between Grades 0–1 and Grades 2–3. Multivariate analysis demonstrated that patients with V65 ≥ 17% had a significantly increased risk (P = 0.032) of Grade 2 or 3 rectal bleeding. Of the 28 patients of Grade 2 or 3 rectal bleeding, 17 patients (60.7%) were cured by a single session of APC, while the other 11 patients required two sessions. Thus, none of the patients had any further rectal bleeding after the second APC session.     

Relationship of Eating Patterns and Metabolic Parameters,and Teneligliptin Treatment: Interim Results from Post-marketing Surveillance in Japanese Type 2 Diabetes Patients

Introduction

Healthy eating is a critical aspect of the prevention and management of type 2 diabetes (T2DM). Disrupted eating patterns can result in poor glucose control and increase the likelihood of diabetic complications. Teneligliptin inhibits dipeptidyl peptidase-4 activity for 24 h and suppresses postprandial hyperglycemia after all three daily meals. This interim analysis of data from the large-scale post-marketing surveillance of teneligliptin (RUBY) in Japan examined eating patterns and their relationship with metabolic parameters and diabetic complications. We also examined whether eating patterns affected safety and efficacy of teneligliptin.

Methods

We analyzed baseline data from survey forms collected in RUBY between May 2013 and June 2017, including patient characteristics, metabolic parameters, and eating patterns (eating three meals per day or not; timing of evening meal) before teneligliptin treatment was initiated. Safety and efficacy of 12 months’ teneligliptin (20–40 mg/day) treatment was assessed.

Results

Data from 10,532 patients were available for analysis. Most patients who did not eat three meals per day (n??=757) or who ate their evening meal after 10 PM (n??=206) were 64 years old or younger. At baseline, glycated hemoglobin (HbA1c), fasting blood glucose, triglycerides, total and low-density lipoprotein cholesterol, body mass index, alanine aminotransferase, and aspartate aminotransferase levels were higher in those patients who did not eat three meals per day (p?<?0.05) or who ate their evening meal late (p?<?0.05). Diabetic complications were more common in patients who did not eat three meals per day. Treatment with teneligliptin reduced HbA1c over 6 or 12 months across all eating patterns, with a low incidence of adverse drug reactions.

Conclusions

Eating patterns may be associated with altered metabolic parameters and diabetic complications among Japanese patients with T2DM. Teneligliptin may be well tolerated and improve hyperglycemia in patients with T2DM irrespective of eating patterns.

Funding

Mitsubishi Tanabe Pharma Corporation and Daiichi Sankyo Co. Ltd.

Trial Registration Number

Japic CTI-153047.

     

72-Week Safety and Tolerability of Dimethyl Fumarate in Japanese Patients with Relapsing-remitting Multiple Sclerosis: Analysis of the Randomised,Double Blind,Placebo-Controlled,Phase III APEX Study and its Open-Label Extension

Introduction

The long-term safety of dimethyl fumarate (DMF) in patients with relapsing-remitting multiple sclerosis (RRMS) has been studied in mainly Caucasian patients. The present interim analysis aimed to evaluate the 72-week safety of DMF in Japanese patients with RRMS.

Methods

Safety data of Japanese subjects enrolled in the 24-week randomised, double-blind, placebo-controlled APEX study (Part I) and its following open-label extension (Part II) were analysed at 72 weeks from the beginning of Part I. In Part I, subjects were randomised to DMF treatment or matching placebo while all subjects received DMF treatment during Part II. Adverse events (AEs) reported throughout the study period were recorded.

Results

Overall, 109 Japanese subjects completed 72 weeks of treatment. The incidence of AEs and serious AEs was 95% and 19%, respectively, in the DMF group compared with 84% and 18%, respectively, in the placebo group at 24 weeks. Common AEs (at least 5%) reported with treatment included nasopharyngitis, flushing, hot flush, gastrointestinal events, pruritus, rash, headache, increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST). AEs led to discontinuation of DMF in 5% of patients and included MS relapse, flushing, abdominal pain, liver disorder and increased ALT/AST. After an initial decrease from baseline of 17% in the DMF group at week 24, the mean lymphocyte counts stabilised and were maintained until week 72. No opportunistic/serious infections nor malignancies were reported with DMF treatment. The incidences of AEs, serious AEs, and discontinuation due to AEs were similar between the DMF and the placebo groups.

Conclusion

The 72-week safety profile of DMF in Japanese patients with RRMS was consistent with previous studies that enrolled mostly Caucasian patients, with a lower incidence of flushing and related symptoms and a lower reduction in the lymphocyte count compared with previous reports.

Trial Registration

ClinicalTrials.gov identifier NCT01838668.

Funding

Biogen Japan Ltd.