Induction of fetal meiotic oocytes from embryonic stem cells in cynomolgus monkeys

Human in vitro oogenesis provides a framework for clarifying the mechanism of human oogenesis. To create its benchmark, it is vital to promote in vitro oogenesis using a model physiologically close to humans. Here, we establish a foundation for in vitro oogenesis in cynomolgus (cy) monkeys (Macaca fascicularis): cy female embryonic stem cells harboring one active and one inactive X chromosome (Xa and Xi, respectively) differentiate robustly into primordial germ cell-like cells, which in xenogeneic reconstituted ovaries develop efficiently into oogonia and, remarkably, further into meiotic oocytes at the zygotene stage. This differentiation entails comprehensive epigenetic reprogramming, including Xi reprogramming, yet Xa and Xi remain epigenetically asymmetric with, as partly observed in vivo, incomplete Xi reactivation. In humans and monkeys, the Xi epigenome in pluripotent stem cells functions as an Xi-reprogramming determinant. We further show that developmental pathway over-activations with suboptimal up-regulation of relevant meiotic genes impede in vitro meiotic progression. Cy in vitro oogenesis exhibits critical homology with the human system, including with respect to bottlenecks, providing a salient model for advancing human in vitro oogenesis.

Impact of Magnetic Field Configuration on Heat Transport in Stellarators and Heliotrons

We assess the magnetic field configuration in modern fusion devices by comparing experiments with the same heating power, between a stellarator and a heliotron. The key role of turbulence is evident in the optimized stellarator, while neoclassical processes largely determine the transport in the heliotron device. Gyrokinetic simulations elucidate the underlying mechanisms promoting stronger ion scale turbulence in the stellarator. Similar plasma performances in these experiments suggests that neoclassical and turbulent transport should both be optimized in next step reactor designs.

W-band millimeter-wave back-scattering system for high wavenumber turbulence measurements in LHD

A 90 GHz W-band millimeter-wave back-scattering system is designed and installed for measuring electron scale turbulence (k_⊥ρ_s ∼ 40). A metal lens relay antenna is used for in-vessel beam focusing, and a beam diameter of less than 40 mm is achieved in the plasma core region. This antenna can be steered at an angle of 159° ± 6°, which almost covers the plasma radius. The estimated size of the scattering volume is ∼105 mm at the edge and 135 mm at the core, respectively. A 60 m corrugated waveguide is used to achieve a low transmission loss of ∼8 dB. A heterodyne detection system for millimeter-wave circuits with probing power modulation can distinguish the scattered signal from background noise.

Impact of diabetes mellitus on the early phase arterial healing after drug-eluting stent implantation: a multicenter coronary angioscopic study

Background

Diabetes mellitus (DM) is a strong risk factor for major cardiac and cerebrovascular events. In particular, coronary artery disease with DM is often complicated with complex lesions. Drug-eluting stents (DES) are mainly used for these lesions, and dual-antiplatelet therapy (DAPT) has been used to prevent stent thrombosis. Early arterial healing after DES implantation may enable short DAPT strategy. However, the impact of DM on the arterial healing in the early phase has not been elucidated to date.

Purpose

We evaluated the arterial healing in the early phase after DES implantation using coronary angioscopy (CAS) and compared the findings between DM and non-DM patients.

Methods

This study was a multicenter retrospective observational study. We analyzed CAS findings of 337 lesions from 270 patients which were evaluated 3 to 5 months after DES implantation. Patients were divided into two groups: DM (149 lesions in 118 patients) versus non-DM groups (188 lesions in 152 patients). We assessed neointimal coverage (NIC) grades (maximum, minimum and dominant), thrombus adhesion and maximum yellow color of plaque underneath the stent. NIC was graded as follows: grade 0, stent struts were not covered; grade 1, stent struts were covered by thin layer; grade 2, stent struts were buried under neointima. Yellow color was graded as follows: grade 0, white; grade 1, light yellow; grade 2, yellow; grade 3, intensive yellow.

Results

Minimum NIC coverage grade was lower in DM group than in non-DM group (P=0.002, Figure), while maximum and dominant NIC coverage grades were similar between them (P=0.94 and P=0.59, respectively). Thrombus adhesion (44.3% versus 38.8%, P=0.32) and maximum yellow color grade (P=0.78) were also similar between DM and non-DM groups. Even after the adjustment by the confounding factors such as follow-up duration and primary disease of acute coronary syndrome, DM was an independent factor predicting grade 0 of minimum NIC (odds ratio [OR] 1.83 [95% confidence interval 1.11–3.03], P=0.019).

Conclusion

DM patients showed less covered struts than non-DM patients 3 to 5 months after DES implantation, suggesting that the recent ultra-short DAPT strategy might not be easily applicable to DM patients.

Minimum neointimal coverage grade

Funding Acknowledgement

Type of funding source: None

Mechanistic insights into the evolution of the differential expression of tandemly arrayed cone opsin genes in zebrafish

The genome of many organisms contains several loci consisting of duplicated genes that are arrayed in tandem. The daughter genes produced by duplication typically exhibit differential expression patterns with each other or otherwise experience pseudogenization. Remarkably, opsin genes in fish are preserved after many duplications in different lineages. This fact indicates that fish opsin genes are characterized by a regulatory mechanism that could intrinsically facilitate the differentiation of the expression patterns. However, little is known about the mechanisms that underlie the differential expression patterns or how they were established during evolution. The loci of green (RH2)- and red (LWS)-sensitive cone opsin genes in zebrafish have been used as model systems to study the differential regulation of tandemly arrayed opsin genes. Over a decade of studies have uncovered several mechanistic features that might have assisted the differentiation and preservation of duplicated genes. Furthermore, recent progress in the understanding of the transcriptional process in general has added essential insights. In this article, the current understanding of the transcriptional regulation of differentially expressed tandemly arrayed cone opsin genes in zebrafish is summarized and a possible evolutionary scenario that could achieve this differentiation is discussed.

Controlling gene activation by enhancers through a drug-inducible topological insulator

While regulation of gene-enhancer interaction is intensively studied, its application remains limited. Here, we reconstituted arrays of CTCF-binding sites and devised a synthetic topological insulator with tetO for chromatin-engineering (STITCH). By coupling STITCH with tetR linked to the KRAB domain to induce heterochromatin and disable the insulation, we developed a drug-inducible system to control gene activation by enhancers. In human induced pluripotent stem cells, STITCH inserted between MYC and the enhancer down-regulated MYC. Progressive mutagenesis of STITCH led to a preferential escalation of the gene-enhancer interaction, corroborating the strong insulation ability of STITCH. STITCH also altered epigenetic states around MYC. Time-course analysis by drug induction uncovered deposition and removal of H3K27me3 repressive marks follows and reflects, but does not precede and determine, the expression change. Finally, STITCH inserted near NEUROG2 impaired the gene activation in differentiating neural progenitor cells. Thus, STITCH should be broadly useful for functional genetic studies.

P4704The efficacy of intravascular ultrasound for patients with peripheral artery diseases presenting aorto-iliac artery disease

Background

The use of intravascular ultrasound (IVUS) promotes better clinical outcomes for intervention in complex lesions. However, the data demonstrating whether use of IVUS improves primary patency following stenting for aorto-iliac lesions in patients with peripheral artery disease (PAD) are limited.

Purpose

The purpose of the current study was to investigate the impact of IVUS use on primary patency 12 months after stent implantation for aorto-iliac lesions.

Methods

We analyzed a clinical database of the OMOTENASHI registry (Observational prospective Multicenter registry study on Outcomes of peripheral arTErial disease patieNts treated by AngioplaSty tHerapy in aortoIliac artery), registering symptomatic PAD patients (Rutherford category 2, 3, or 4) undergoing endovascular therapy for aorto-iliac lesions between January 2014 and April 2016 in Japan. The current study analyzed 803 patients who underwent self-expandable stent implantation at 61 centers with the institutional volume known. The primary endpoint was 12-month restenosis, defined as ≥50% stenosis on computed tomography or angiography, or a peak systolic velocity ratio ≥2.5 on duplex ultrasound. When treatment strategies, endovascular procedures and clinical outcomes were compared between the patients treated with IVUS use and those treated without IVUS use, the propensity score matching was performed to minimize the inter-group difference in baseline characteristics.

Results

A total of 545 patients (67.9%) underwent IVUS-supported stent implantation. Patients treated with IVUS use had a lower prevalence of regular dialysis, whereas they had a higher prevalence of TASC II class D and chronic total occlusion. In patients treated with IVUS use, carbon dioxide contrast agent were more often used, and 0.035-inch guidewire was less frequently selected. Implanted stents in these patients were longer and smaller in diameter. The propensity score matching extracted 138 pairs, with no remarkable intergroup difference in baseline characteristics. Procedure time ≤1 hour was less frequent in patients treated with IVUS use; their radiation time was longer. Endovascular strategies, as well as postoperative medication were not significantly different between patients with and without IVUS use. The 12-month restenosis risk was not significantly different between patients with and without IVUS use (10.2% [6.9 to 14.9%] versus 10.3% [5.4 to 18.6%], P=0.99).

Conclusion

IVUS use in aorto-iliac stenting for patients with PAD was not associated with primary patency at 12 months.

Acknowledgement/Funding

None

P4711The prognostic impact of infrapopliteal arterial calcification on wound healing in patients with critical limb ischemia

Background

Critical limb ischemia (CLI) is the most progressed manifestation of peripheral artery disease. Although patients with CLI commonly complicate with severely calcified lesions in infrapopliteal lesions, the prognostic impact of infrapopliteal arterial calcification on wound healing in patients with CLI has not been systematically studied.

Purpose

The aim of current study was to elucidate the prognostic impact of infrapopliteal arterial calcification on wound healing in CLI undergoing endovascular therapy (EVT).

Methods

This study enrolled 639 CLI patients with tissue loss (age 74±10 years, male 62%, diabetes 69%, hemodialysis 57%, Rutherford class 5 77%, class 6 23%) primarily treated with EVT for the infrapopliteal lesions between April 2010 and December 2015. Arterial calcification was assessed by high intensity fluoroscopy and classified into 3 groups as follows; 1) none, 2) unilateral and 3) bilateral calcification. The primary outcome measure was complete wound healing. The predictors of the outcome were evaluated by Cox proportional hazards regression analysis.

Results

During a mean follow-up period of 22±19 months, 1-year wound healing rate were 59.0%. In Kaplan-Meier analysis, 1-year wound healing rate was worse in patients with bilateral calcification than in those with unilateral or none calcification (Figure, 46.2% versus 55.1% versus 67.8%, P<0.001). After multivariate analysis, the predictors of wound healing were non-ambulatory status (hazard ratio (HR) 0.67 [95% confidential interval (CI) 0.53–0.85], P=0.001) and bilateral calcification (HR 0.75 [95% CI 0.47–0.98], versus none or unilateral calcification, P=0.036).

Figure 1

Conclusion

Infrapopliteal Arterial calcification as well as non-ambulatory status was associated with wound healing in patients with CLI.

P3386Angioscopic comparison between polymer-free biolimus A9-coated stent and durable polymer drug-eluting stent 10 months after the implantation

Background

Polymer-free biolimus A9-coated stent (DCS) has currently emerged as expected better arterial healing compared to durable polymer drug-eluting stent (DP-DES). However, superiority of DCS on arterial healing over DP-DES has not been well elucidated using intracoronary images.

Methods

This study examined 288 stents in 224 patients with de novo coronary artery lesions. We angioscopically compared 55 DCS from 35 patients with 233 DP-DES from 189 patients 10±2 months after the implantation. We assessed thrombus adhesion, which is a marker of incomplete re-endothelialization. Dominant neointimal coverage (NIC) grade, heterogeneity of NIC and maximum yellow color of plaque underneath the stent were also evaluated. Neointimal coverage was graded as follows: grade 0, stent struts exposed; grade 1, struts bulged into the lumen, although covered; grade 2, struts embedded by the neointima, but translucent; grade 3, struts fully embedded and invisible. NIC was judged as heterogeneous when differences in the NIC grade became apparent. Yellow plaque was graded as follows: grade 0, white; grade 1, light yellow; grade 2, yellow; grade 3, intensive yellow.

Results

Thrombus adhesion was similar between DCS and DP-DES (29% versus 23%, P=0.32). Dominant NIC was greater in DCS than in BP-DES (P<0.001), while NIC was more heterogeneous in DCS than in BP-DES (P=0.001, Figure). Maximum yellow color of stented segment was similar between DCS and DP-DES (P=0.09).

Conclusion

DCS provided similar thrombus adhesion to DP-DES, which suggested similar re-endothelialization 10 months after implantation. However, DCS showed thick and heterogeneous NIC compared to DP-DES. The specific feature of polymer-free and Biolimus A9 would cause the difference, and further investigation is necessary to evaluate the longer-term safety and efficacy.

Acknowledgement/Funding

None

P1035Factors associated with quality-of-life improvement after catheter ablation of atrial fibrillation: insights from the Kansai Plus Atrial Fibrillation (KPAF) registry

Background

Improving the quality of life (QoL) is one of the main purposes of catheter ablation (CA) of persistent atrial fibrillation (AF). Factors associated with QoL improvement after CA of AF patients have not been clarified. The Kansai Plus Atrial Fibrillation (KPAF) Registry is a multi-center registry enrolling more than 5,000 consecutive patients undergoing the first radiofrequency catheter ablation of AF.

Purpose

The aim of this study was to investigate the QoL change after AF ablation and its associated factors.

Methods

A total of 2030 patients in whom the QoL score was assessed before and one year after the ablation were enrolled from the KPAF registry (age 64±10 years, 75% male, paroxysmal 66%, CHADS2 score 1.1±1.1). The QoL was evaluated using the AF specific QoL evaluation method (AFQLQ), which scores the patient QoL within a range of 0–98 points.

Results

Overall, catheter ablation showed a significant increase in the AFQLQ score (68±19 vs. 86±13 points, P<0.01). AF recurrence was observed in 372 cases (18%) during a 1-year follow-up period. A multivariate analysis showed that AF recurrence, symptomatic AF, long AF duration, high preprocedural heart rate (>110 bpm) and small left atrial diameter were independent predictors of a QoL improvement defined as a >10% score increase.

Multivariate analysis

Conclusions

CA of AF significantly improved the QoL. AF recurrence was one of the strong factors associated with QoL improvement. Symptomatic AF, long AF duration, high preprocedural heart rate and small left atrial diameter were independent predictors of QoL improvement.

P1916A novel echo-guided approach of cryoballoon ablation without using contrast medium

Background

Pulmonary vein isolation (PVI) using cryoballoon requires contrast medium injection for the confirmation of appropriate venous occlusion. However, some patients have contra-indications against contrast use such as allergy for contrast medium, bronchial asthma or renal dysfunction. We hypothesized that intra-cardiac echocardiographic observation of microbubble leakage after saline injection from the cryoballoon lumen can be used as a maker of incomplete venous occlusion.

Purpose

The aim of this study was to assess the effect of echo-guided approach using saline injection on the acute clinical outcomes as well as the amount of contrast medium.

Methods

Twenty consecutive patients with paroxysmal atrial fibrillation (AF) were studied. They had any reason to avoid using contrast medium. Plain CT scan was performed in all cases to understand the anatomical features. Intra-cardiac echocardiography was used in all cases to guide transseptal puncture and to confirm pulmonary-vein occlusion. Procedural results and clinical outcomes were compared with patients who were performed by the conventional method (n=279).

Results

In all study patients, we could perform PVI without using contrast medium. A total of 2 patients required touch-up ablation using radiofrequency ablation catheter. The procedure time (85±23 vs 86±27 min, P=0.84), the dose of radiation exposure (108±78 vs. 140±133 mmGy/m2, P=0.29), and ratio of requiring touch-up ablation (5% vs 4%, P=0.81) were similar between the study group and the reference group. There was no significant difference in the AF-free survival rate (73% vs. 76%, P=0.79) during a follow-up period of 14±6 months.

Images of ICE

Conclusion

Echo-guided approach using saline infusion was effective and less invasive in terms of reduction of contrast use.

P6241Two-year clinical outcomes of biodegradable polymer versus durable polymer drug-eluting stent implantation in hemodialysis patients after percutaneous coronary intervention

Background

Biodegradable polymer drug-eluting stent (BP-DES) has been developed to improve clinical outcomes after percutaneous coronary intervention (PCI) for patients presenting coronary artery disease (CAD). Although BP-DES showed non-inferior safety and efficacy to durable polymer DES (DP-DES) in several randomized clinical trials, hemodialysis (HD) patients, who have been well known as high risk population for adverse events, were excluded in the most of trials. Therefore, there are limited data comparing the clinical outcomes between BP-DES and DP-DES in HD patients with CAD after PCI.

Purpose

The purpose of this study was to investigate clinical outcomes in HD patients after BP-DES implantation compared with those after DP-DES implantation.

Methods

We retrospectively analyzed 234 HD patients (male 74%, mean age 71±10 years) undergoing PCI for 404 lesions with 472 DESs (71 patients for 138 lesions with 170 BP-DESs [91 Ultimaster and 79 Synergy] and 163 HD patients for 266 lesions with 302 DP-DESs [219 Xience, 53 Promus and 30 Resolute]) from 2011 to 2017. Two-year clinical outcomes were compared between BP-DES group and DP-DES group. The primary outcome measure was the incidence of target lesion revascularization (TLR), while the secondary outcome measures were the occurrence of cardiac death (CD), stent thrombosis (ST), myocardial infraction (MI), target vessel revascularization (TVR), non-TVR and major adverse cardiac event (MACE) defined as a composite of CD, MI, and TVR. Outcome measures were estimated by the Kaplan-Meier method and the differences between BP-DES group and DP-DES group were assessed by the log-rank test. We also conducted Cox's proportional hazard model to identify predictors for TLR occurrence.

Results

Baseline patient and lesion characteristics were similar between the two groups. The two-year incidence of TLR was not significantly different between BP-DES group and DP-DES group (14.1% vs. 22.2%, p=0.391). The two-year incidences of CD (17.3% vs. 17.5%, p=0.381), ST (0% vs. 3.9%, p=0.133), MI (4.2% vs. 5.8%, p=0.965), TVR (21.3% vs. 27.5%, p=0.586), non-TVR (26.1% vs. 31.3%, p=0.439) and MACE (41.1% vs. 42.6%, p=0.526) were also not different between the two groups. After multivariate analysis, diabetes mellitus (hazard ratio 1.97; 95% confidence interval 1.03–3.78, p=0.004) was independently associated with TLR occurrence in HD patients.

Two-year clinical outcomes of HD patient

Conclusions

At two-year follow-up after PCI, BP-DES had comparable safety and efficacy profiles to DP-DES in HD patients presenting CAD.

Acknowledgement/Funding

None

Microwave frequency comb Doppler reflectometer applying fast digital data acquisition system in LHD

We succeeded in increasing the radial observation points of the microwave frequency comb Doppler reflectometer system from 8 to 20 (or especially up to 45) using the high sampling rate of 40 GS/s digital signal processing. For a new acquisition system, the estimation scheme of the Doppler shifted frequency is constructed and compared with the conventional technique. Also, the fine radial profile of perpendicular velocity is obtained, and it is found that the perpendicular velocity profile is consistent with the E × B drift velocity one.

Cold thermal oral stimulation produces immediate excitability in human pharyngeal motor cortex

BACKGROUND

Current strategies of swallowing therapy include facilitation of swallowing initiation by sensory modulation. Although thermal tactile oral stimulation is a common method to treat dysphagic patients to improve swallowing movement, little is known about the possible mechanisms. This study is aimed to investigate whether thermal oral (tongue) stimulation can modulate the cortico-pharyngeal neural motor pathway in humans.

METHODS

Eighteen healthy volunteers participated and were intubated with an intraluminal catheter for recording pharyngeal electromyography. Each participant underwent baseline transcranial magnetic stimulation (TMS) cortico-pharyngeal motor evoked potential (MEP) measurements bilaterally. MEPs were then measured during thermal stimulation over the dorsal tongue, applied using the Peltier device at three different temperatures; 45°C, 37°C, and 15°C, in a pre-ordered manner. Each of the three temperatures was given twice with a 5-min resting time between each trial. Averaged MEP amplitude changes were analyzed using ANOVA and post-hoc t-tests.

KEY RESULTS

Two-way repeated measures ANOVA with factors of Temperature × Trial in amplitude of MEP demonstrated a significant effect of Temperature both in the stronger (F_2,34  = 5.775, P = .007) and weaker (F_2,34  = 4.771, P = .017) pharyngeal hemispheres. Subsequent post-hoc tests showed the significant increase in pharyngeal MEPs at 15° compared to 37° in both hemispheres (P < .05).

CONCLUSIONS & INFERENCES

Cold oral stimulation was able to induce significant changes in pharyngeal cortical excitability, demonstrating evidence for a sensorimotor interaction between oral and pharyngeal cortical areas.

Control of directionality of chromatin folding for the inter- and intra-domain contacts at the Tfap2c-Bmp7 locus

BACKGROUND

Contact domains of chromatin serve as a fundamental unit to regulate action of enhancers for target genes. Looping between a pair of CCCTC-binding factor (CTCF)-binding sites in convergent orientations underlies the formation of contact domains, while those in divergent orientations establish domain boundaries. However, every CTCF site is not necessarily engaged in loop or boundary structures, leaving functions of CTCF in varied genomic contexts still elusive. The locus containing Tfap2c and Bmp7 encompasses two contact domains separated by a region between the two genes, termed transition zone (TZ), characterized by two arrays of CTCF sites in divergent configuration. In this study, we created deletion and inversion alleles of these and other regions across the locus and investigated how they impinge on the conformation.

RESULTS

Deletion of the whole two CTCF arrays with the CRISPR/Cas9 system resulted in impairment of blocking of chromatin contacts by the TZ, as assessed by the circular chromatin conformation capture assay (4C-seq). Deletion and inversion of either of the two arrays similarly, but less pronouncedly, led to reduction in the blocking activity. Thus, the divergent configuration provides the TZ with the strong boundary activity. Uniquely, we show the TZ harbors a 50-kb region within one of the two arrays that contacts broadly with the both flanking intervals, regardless of the presence or orientation of the other CTCF array. Further, we show the boundary CTCF array has little impact on intra-domain folding; instead, locally associating CTCF sites greatly affect it.

CONCLUSIONS

Our results show that the TZ not only separates the two domains, but also bears a wide interval that shows isotropic behavior of chromatin folding, indicating a potentially complex nature of actual boundaries in the genome. We also show that CTCF-binding sites inside a domain greatly contribute to the intra-domain folding of chromatin. Thus, the study reveals diverse and context-dependent roles of CTCF in organizing chromatin conformation at different levels.

Novel analysis technique for measuring edge density fluctuation profiles with reflectometry in the Large Helical Device

A new method for measuring density fluctuation profiles near the edge of plasmas in the Large Helical Device (LHD) has been developed utilizing reflectometry combined with pellet-induced fast density scans. Reflectometer cutoff location was calculated by proportionally scaling the cutoff location calculated with fast far infrared laser interferometer (FIR) density profiles to match the slower time resolution results of the ray-tracing code LHD-GAUSS. Plasma velocity profile peaks generated with this reflectometer mapping were checked against velocity measurements made with charge exchange spectroscopy (CXS) and were found to agree within experimental uncertainty once diagnostic differences were accounted for. Measured density fluctuation profiles were found to peak strongly near the edge of the plasma, as is the case in most tokamaks. These measurements can be used in the future to inform inversion methods of phase contrast imaging (PCI) measurements. This result was confirmed with both a fixed frequency reflectometer and calibrated data from a multi-frequency comb reflectometer, and this method was applied successfully to a series of discharges. The full width at half maximum of the turbulence layer near the edge of the plasma was found to be only 1.5-3 cm on a series of LHD discharges, less than 5% of the normalized minor radius.

Improvement of Pancreatic Islet Isolation Outcomes Using Glutamine Perfusion during Isolation Procedure

During procurement, isolation, and transplantation, islets are exposed to high levels of oxidative stress triggering a variety of signaling pathways that can ultimately lead to cell death. Glutamine is an important cellular fuel and an essential precursor for the antioxidant glutathione. The aim of this study was to examine the role of intraductal glutamine administration in facilitating recovery of isolated rat islets from pancreases subjected to a clinically relevant period of warm ischemia. Islets were isolated in Sprague-Dawley (SD) rats (n= 18 per group). Pancreata in groups 1 and 2 were procured immediately while groups 3 and 4 were subjected to 30-min warm ischemia. Groups 2 and 4 were treated intraductally with 5 mM glutamine prior to pancreatectomy. Exposure to 30-min warm ischemia significantly reduced islet yield [groups 1 & 2 (nonischemia): 503 ± 29 islets/rat vs. groups 3 & 4 (ischemia): 247 ± 26 islets/rat; p < 0.05]. Intraductal glutamine treatment significantly improved islet yield when pancreata were subjected to 30-min warm ischemia [144 ± 16 islets/rat without glutamine (group 3) vs. 343 ± 36 islets/rat with glutamine (group 4), p < 0.05]. Glutamine also significantly improved islet viability (values were 50 ± 4% in group 4 vs. 27 ± 3% in group 3, p < 0.05). Similarly, glutathione (reduced) levels were significantly elevated in both glutamine-treated groups; however, this increase was greatest in tissues exposed to ischemia (2.76 ± 0.04 nmol/mg protein in group 4 vs. 1.66 ± 0.04 nmol/mg protein in group 3, p < 0.05). Intraductal glutamine administration considerably improves the islet yield, viability, and augments endogenous glutathione levels in pancreata procured after a clinically relevant period of ischemia. Intraductal administration of glutamine at the time of digestive enzyme delivery into the harvested pancreas may represent a simple yet effective tool to improve islet yields in clinical isolations.

Roles and regulation of bone morphogenetic protein-7 in kidney development and diseases

The gene encoding bone morphogenetic protein-7 (BMP7) is expressed in the developing kidney in embryos and also in the mature organ in adults. During kidney development, expression of BMP7 is essential to determine the final number of nephrons in and proper size of the organ. The secreted BMP7 acts on the nephron progenitor cells to exert its dual functions: To maintain and expand the progenitor population and to provide them with competence to respond to differentiation cues, each relying on distinct signaling pathways. Intriguingly, in the adult organ, BMP7 has been implicated in protection against and regeneration from injury. Exogenous administration of recombinant BMP7 to animal models of kidney diseases has shown promising effects in counteracting inflammation, apoptosis and fibrosis evoked upon injury. Although the expression pattern of BMP7 has been well described, the mechanisms by which it is regulated have remained elusive and the processes by which the secretion sites of BMP7 impinge upon its functions in kidney development and diseases have not yet been assessed. Understanding the regulatory mechanisms will pave the way towards gaining better insight into the roles of BMP7, and to achieving desired control of the gene expression as a therapeutic strategy for kidney diseases.

Spatially differentiated expression of quadruplicated green-sensitive RH2 opsin genes in zebrafish is determined by proximal regulatory regions and gene order to the locus control region

Background

Fish are remarkably diverse in repertoires of visual opsins by gene duplications. Differentiation of their spatiotemporal expression patterns and absorption spectra enables fine-tuning of feature detection in spectrally distinct regions of the visual field during ontogeny. Zebrafish have quadruplicated green-sensitive (RH2) opsin genes in tandem (RH2-1, −2, −3, −4), which are expressed in the short member of the double cones (SDC). The shortest wavelength RH2 subtype (RH2-1) is expressed in the central to dorsal area of the adult retina. The second shortest wave subtype (RH2-2) is expressed overlapping with RH2-1 but extending outside of it. The second longest wave subtype (RH2-3) is expressed surrounding the RH2–2 area, and the longest wave subtype (RH2-4) is expressed outside of the RH2-3 area broadly occupying the ventral area. Expression of the four RH2 genes in SDC requires a single enhancer (RH2-LCR), but the mechanism of their spatial differentiation remains elusive.

Results

Functional comparison of the RH2-LCR with its counterpart in medaka revealed that the regulatory role of the RH2-LCR in SDC-specific expression is evolutionarily conserved. By combining the RH2-LCR and the proximal upstream region of each RH2 gene with fluorescent protein reporters, we show that the RH2-LCR and the RH2-3 proximal regulatory region confer no spatial selectivity of expression in the retina. But those of RH2-1, −2 and −4 are capable of inducing spatial differentiation of expression. Furthermore, by analyzing transgenic fish with a series of arrays consisting of the RH2-LCR and multiple upstream regions of the RH2 genes in different orders, we show that a gene expression pattern related to an upstream region is greatly influenced by another flanking upstream region in a relative position-dependent manner.

Conclusions

The zebrafish RH2 genes except RH2-3 acquired differential cis-elements in the proximal upstream regions to specify the differential expression patterns. The input from these proximal elements collectively dictates the actual gene expression pattern of the locus, context-dependently. Importantly, competition for the RH2-LCR activity among the replicates is critical in this collective regulation, facilitating differentiation of expression among them. This combination of specificity and generality enables seemingly complicated spatial differentiation of duplicated opsin genes characteristic in fish.

Electronic supplementary material

The online version of this article (doi:10.1186/s12863-015-0288-7) contains supplementary material, which is available to authorized users.

Adult stem-like cells in kidney

Human pluripotent cells are promising for treatment for kidney diseases, but the protocols for derivation of kidney cell types are still controversial. Kidney tissue regeneration is well confirmed in several lower vertebrates such as fish, and the repair of nephrons after tubular damages is commonly observed after renal injury. Even in adult mammal kidney, renal progenitor cell or system is reportedly presents suggesting that adult stem-like cells in kidney can be practical clinical targets for kidney diseases. However, it is still unclear if kidney stem cells or stem-like cells exist or not. In general, stemness is defined by several factors such as self-renewal capacity, multi-lineage potency and characteristic gene expression profiles. The definite use of stemness may be obstacle to understand kidney regeneration, and here we describe the recent broad findings of kidney regeneration and the cells that contribute regeneration.

A discrete transition zone organizes the topological and regulatory autonomy of the adjacent tfap2c and bmp7 genes

Despite the well-documented role of remote enhancers in controlling developmental gene expression, the mechanisms that allocate enhancers to genes are poorly characterized. Here, we investigate the cis-regulatory organization of the locus containing the Tfap2c and Bmp7 genes in vivo, using a series of engineered chromosomal rearrangements. While these genes lie adjacent to one another, we demonstrate that they are independently regulated by distinct sets of enhancers, which in turn define non-overlapping regulatory domains. Chromosome conformation capture experiments reveal a corresponding partition of the locus in two distinct structural entities, demarcated by a discrete transition zone. The impact of engineered chromosomal rearrangements on the topology of the locus and the resultant gene expression changes indicate that this transition zone functionally organizes the structural partition of the locus, thereby defining enhancer-target gene allocation. This partition is, however, not absolute: we show that it allows competing interactions across it that may be non-productive for the competing gene, but modulate expression of the competed one. Altogether, these data highlight the prime role of the topological organization of the genome in long-distance regulation of gene expression.

The specificity of enhancer-gene interactions is fundamental to the execution of gene regulatory programs underpinning embryonic development and cell differentiation. However, our understanding of the mechanisms conferring specificity to enhancers and target gene interactions is limited. In this study, we characterize the cis-regulatory organization of a large genomic locus consisting of two developmental genes, Tfap2c and Bmp7. We show that this locus is structurally partitioned into two distinct domains by the constitutive action of a discrete transition zone located between the two genes. This separation restricts selectively the functional action of enhancers to the genes present within the same domain. Interestingly, the effects of this region as a boundary are relative, as it allows some competing interactions to take place across domains. We show that these interactions modulate the functional output of a brain enhancer on its primary target gene resulting in the spatial restriction of its expression domain. These results support a functional link between topological chromatin domains and allocation of enhancers to genes. They further show that a precise adjustment of chromatin interaction levels fine-tunes gene regulation by long-range enhancers.

Functional and topological characteristics of mammalian regulatory domains

Long-range regulatory interactions play an important role in shaping gene-expression programs. However, the genomic features that organize these activities are still poorly characterized. We conducted a large operational analysis to chart the distribution of gene regulatory activities along the mouse genome, using hundreds of insertions of a regulatory sensor. We found that enhancers distribute their activities along broad regions and not in a gene-centric manner, defining large regulatory domains. Remarkably, these domains correlate strongly with the recently described TADs, which partition the genome into distinct self-interacting blocks. Different features, including specific repeats and CTCF-binding sites, correlate with the transition zones separating regulatory domains, and may help to further organize promiscuously distributed regulatory influences within large domains. These findings support a model of genomic organization where TADs confine regulatory activities to specific but large regulatory domains, contributing to the establishment of specific gene expression profiles.

TRACER: a resource to study the regulatory architecture of the mouse genome

BACKGROUND

Mammalian genes are regulated through the action of multiple regulatory elements, often distributed across large regions. The mechanisms that control the integration of these diverse inputs into specific gene expression patterns are still poorly understood. New approaches enabling the dissection of these mechanisms in vivo are needed.

RESULTS

Here, we describe TRACER (http://tracerdatabase.embl.de), a resource that centralizes information from a large on-going functional exploration of the mouse genome with different transposon-associated regulatory sensors. Hundreds of insertions have been mapped to specific genomic positions, and their corresponding regulatory potential has been documented by analysis of the expression of the reporter sensor gene in mouse embryos. The data can be easily accessed and provides information on the regulatory activities present in a large number of genomic regions, notably in gene-poor intervals that have been associated with human diseases.

CONCLUSIONS

TRACER data enables comparisons with the expression pattern of neighbouring genes, activity of surrounding regulatory elements or with other genomic features, revealing the underlying regulatory architecture of these loci. TRACER mouse lines can also be requested for in vivo transposition and chromosomal engineering, to analyse further regions of interest.

Bipolar cell-photoreceptor connectivity in the zebrafish (Danio rerio) retina

Bipolar cells convey luminance, spatial, and color information from photoreceptors to amacrine and ganglion cells. We studied the photoreceptor connectivity of 321 bipolar cells in the adult zebrafish retina. 1,1'-Dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) was inserted into whole-mounted transgenic zebrafish retinas to label bipolar cells. The photoreceptors that connect to these DiI-labeled cells were identified by transgenic fluorescence or their positions relative to the fluorescent cones, as cones are arranged in a highly ordered mosaic: rows of alternating blue- (B) and ultraviolet-sensitive (UV) single cones alternate with rows of red-(R) and green-sensitive (G) double cones. Rod terminals intersperse among cone terminals. As many as 18 connectivity subtypes were observed, 9 of which-G, GBUV, RG, RGB, RGBUV, RGRod, RGBRod, RGBUVRod, and RRod bipolar cells-accounted for 96% of the population. Based on their axon terminal stratification, these bipolar cells could be further subdivided into ON, OFF, and ON-OFF cells. The dendritic spread size, soma depth and size, and photoreceptor connections of the 308 bipolar cells within the nine common connectivity subtypes were determined, and their dendritic tree morphologies and axonal stratification patterns compared. We found that bipolar cells with the same axonal stratification patterns could have heterogeneous photoreceptor connectivity whereas bipolar cells with the same dendritic tree morphology usually had the same photoreceptor connectivity, although their axons might stratify on different levels.

A single enhancer regulating the differential expression of duplicated red-sensitive opsin genes in zebrafish

A fundamental step in the evolution of the visual system is the gene duplication of visual opsins and differentiation between the duplicates in absorption spectra and expression pattern in the retina. However, our understanding of the mechanism of expression differentiation is far behind that of spectral tuning of opsins. Zebrafish (Danio rerio) have two red-sensitive cone opsin genes, LWS-1 and LWS-2. These genes are arrayed in a tail-to-head manner, in this order, and are both expressed in the long member of double cones (LDCs) in the retina. Expression of the longer-wave sensitive LWS-1 occurs later in development and is thus confined to the peripheral, especially ventral-nasal region of the adult retina, whereas expression of LWS-2 occurs earlier and is confined to the central region of the adult retina, shifted slightly to the dorsal-temporal region. In this study, we employed a transgenic reporter assay using fluorescent proteins and P1-artificial chromosome (PAC) clones encompassing the two genes and identified a 0.6-kb “LWS-activating region” (LAR) upstream of LWS-1, which regulates expression of both genes. Under the 2.6-kb flanking upstream region containing the LAR, the expression pattern of LWS-1 was recapitulated by the fluorescent reporter. On the other hand, when LAR was directly conjugated to the LWS-2 upstream region, the reporter was expressed in the LDCs but also across the entire outer nuclear layer. Deletion of LAR from the PAC clones drastically lowered the reporter expression of the two genes. These results suggest that LAR regulates both LWS-1 and LWS-2 by enhancing their expression and that interaction of LAR with the promoters is competitive between the two genes in a developmentally restricted manner. Sharing a regulatory region between duplicated genes could be a general way to facilitate the expression differentiation in duplicated visual opsins.

Among vertebrates, fish may have the most advanced color vision. They have greatly varied repertoires of color sensors called visual opsins, possibly reflecting evolutionary adaptation to their diverse photic environments in water, and are an excellent model to study the evolution of vertebrate color vision. This is achieved by multiplying opsin genes and differentiating their absorption light spectra and expression patterns. However, little is understood regarding how the opsin genes are regulated to achieve the differential expression pattern. In this study, we focused on the duplicated red-sensitive opsin genes of zebrafish to tackle this problem. We discovered an “enhancer” region near the two red opsin genes that plays a crucial role in their differential expression pattern. Our results suggest that the two red opsin genes interact with the enhancer competitively in a developmentally restricted manner. Sharing a regulatory region could be a general way to facilitate the expression differentiation in duplicated visual opsin genes.

Stemness signature of BMI1 and clinical outcome in esophageal cancer patients undergoing neoadjuvant chemoradiotherapy

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Background: The polycomb group (PcG) family BMI1, acting downstream of the hedgehog (Hh) pathway, plays an essential role in the self-renewal of hematopoietic, neural, and intestinal stem cells, and is dysregulated in many types of cancer. Our recent report has demonstrated that Gli-1 nuclear expression indicative of Hh signalling activation can predict very poorer prognosis of esophageal squamous cell carcinomas (ESCCs)(Br J Cancer 2008). As data were not available on the clinical role of BMI1 expression, we analyzed whether it could be also used to predict disease progression and prognosis in ESCC patients undergoing neoadjuvant chemoradiotherapy (CRT). Methods: BMI1, Gli-1, and p16INK4A expressions were evaluated in 78 ESCC patients by immunohistochemical staining. All patients underwent preoperative chemoradiotherapy; 40 Gy irradiation plus FP (5- FU and CDDP) regimen. Results: In total, 24 out of 78 patients (30.8%) showed BMI1 positive expression. All Gli- 1 nuclear positive cancers expressed BMI1. There was no significant correlation between p16INK4A expression and BMI1 expression. Overall survival (OS) was significantly correlated with the absence of BMI1 expression. The patients with BMI1-positive cancers showed significantly poorer prognoses than those without (mean disease-free survival (DFS) time 16.8 vs 71.2 months, P<0.005; mean OS time 21.8 vs 76.6 months, P<0.001). Conclusions: We demonstrated that BMI1 expression indicative of PcG protein chromatin silencing pathway activation was significantly correlated with esophageal cancer recurrence and poor prognosis after CRT, and that it was not inversely correlated with the presence of the downstream target p16INK4A. These findings suggest that the stemness signature including components of Hh and PcG pathways might be involved in promoting cancer regrowth and progression after CRT, and is thus a potential prognostic biomarker and rational therapeutic target for attacking the “more aggressive” cancer cells causing recurrence.

No significant financial relationships to disclose.

Circulating tumor cells (CTCs) and endothelial cells (CECs) in the diagnosis of malignant pleural mesothelioma (MPM): A single institutional prospective study

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Background: Circulating tumor cell (CTC), a surrogate of distant metastasis, and circulating endothelia cell (CEC), a surrogate of angiogenesis, are potentially useful in the diagnosis of malignant tumors. Following a promising result of our preliminary study showing the diagnostic value of CTC/CEC in malignant pleural mesothelioma (MPM)(Tanaka F, et al. ASCO 2008), we conducted a prospective study. Methods: Patients (pts), who presented at our institute with suspicion or diagnosis of MPM, were eligible in the study. CTCs and CECs in peripheral blood (7.5mL and 4.0mL, respectively) were captured and quantitatively evaluated with the “CellSearch” system without knowledge of clinical characteristics of patients. Results: A total of 92 pts were enrolled into the study, and the final diagnosis was MPM in 68, other malignant tumors in 7, and non-malignant diseases in 17 pts ( Table ). CTC was positive (CTC-count, 1 or more per 7.5mL of the peripheral blood) in 35%(24/68) of MPM pts (range of CTC-count, 0–27 cells/7.5 mL). Among non-malignant pts, 3 pts (18%) showed a positive-CTC, but no patient showed 2 or more CTCs in 7.5mL of the peripheral blood. The mean CEC-count (/4.0mL) was significantly higher in MPM pts than in non-malignant pts (105.1 versus 40.2; p=0.047). When the cut-off value of CEC-count for the diagnosis of MPM was defined as 50(cells/4.0mL), the sensitivity, specificity, positive predictive value, and negative predictive value for the diagnosis of malignant diseases were 66%, 70%, 93%, and 26%, respectively. There was no correlation between CTC-positivity and clinical stage of MPM pts, but was a trend of increase in the mean CEC-count along with tumor progression (mean CEC-count for stage I, II, III, and IV pts: 63.0, 82.4, 95.6, and 116.7, respectively). Conclusions: CTC and CEC are useful clinical markers in the diagnosis of MPM.

[Table: see text]

No significant financial relationships to disclose.

Hedgehog signal activation in oesophageal cancer patients undergoing neoadjuvant chemoradiotherapy

The zinc finger protein glioma-associated oncogene homologue 1 (Gli-1) is a critical component of the Hedgehog (Hh) signalling pathway, which is essential for morphogenesis and stem-cell renewal, and is dysregulated in many cancer types. As data were not available on the role of Gli-1 expression in oesophageal cancer progression, we analysed whether it could be used to predict disease progression and prognosis in oesophageal cancer patients undergoing neoadjuvant chemoradiotherapy (CRT). Among 69 patients with histologically confirmed oesophageal squamous cell carcinomas (ESCCs), 25 showed a pathological complete response after preoperative CRT. Overall survival (OS) was significantly associated with lymph-node metastasis, distant metastasis, and CRT, and was further correlated with the absence of both Gli-1 nuclear expression and residual tumour. All patients with Gli-1 nuclear expression (10.1%) had distant or lymph-node metastasis, and six out of seven died within 13 months. Furthermore, patients with Gli-1 nuclear-positive cancers showed significantly poorer prognoses than those without (disease-free survival: mean DFS time 250 vs 1738 months, 2-year DFS 0 vs 54.9%, P=0.009; OS: mean OS time 386 vs 1742 months, 2-year OS 16.7 vs 54.9%, P=0.001). Our study provides the first evidence that Gli-1 nuclear expression is a strong and independent predictor of early relapse and poor prognosis in ESCC after CRT. These findings suggest that Hh signal activation might promote cancer regrowth and progression after CRT.

Identification of a locus control region for quadruplicated green-sensitive opsin genes in zebrafish

Duplication of opsin genes has a crucial role in the evolution of visual system. Zebrafish have four green-sensitive (RH2) opsin genes (RH2-1, RH2-2, RH2-3, and RH2-4) arrayed in tandem. They are expressed in the short member of the double cones (SDC) but differ in expression areas in the retina and absorption spectra of their encoding photopigments. The shortest and the second shortest wavelength subtypes, RH2-1 and RH2-2, are expressed in the central-to-dorsal retina. The longer wavelength subtype, RH2-3, is expressed circumscribing the RH2-1/RH2-2 area, and the longest subtype, RH2-4, is expressed further circumscribing the RH2-3 area and mainly occupying the ventral retina. The present report shows that a 0.5-kb region located 15 kb upstream of the RH2 gene array is an essential regulator for their expression. When the 0.5-kb region was deleted from a P1-artificial chromosome (PAC) clone encompassing the four RH2 genes and when one of these genes was replaced with a reporter GFP gene, the GFP expression in SDCs was abolished in the zebrafish to which a series of the modified PAC clones were introduced. Transgenic studies also showed that the 0.5-kb region conferred the SDC-specific expression for promoters of a non-SDC (UV opsin) and a nonretinal (keratin 8) gene. Changing the location of the 0.5-kb region in the PAC clone conferred the highest expression for its proximal gene. The 0.5-kb region was thus designated as RH2-LCR analogous to the locus control region of the L-M opsin genes of primates.