Hypoxia-induced immortalization of primary cells depends on Tfcp2L1 expression

Cellular senescence is a stress response mechanism that induces proliferative arrest. Hypoxia can bypass senescence and extend the lifespan of primary cells, mainly by decreasing oxidative damage. However, how hypoxia promotes these effects prior to malignant transformation is unknown. Here we observed that the lifespan of mouse embryonic fibroblasts (MEFs) is increased when they are cultured in hypoxia by reducing the expression of p16INK4a, p15INK4b and p21Cip1. We found that proliferating MEFs in hypoxia overexpress Tfcp2l1, which is a main regulator of pluripotency and self-renewal in embryonic stem cells, as well as stemness genes including Oct3/4, Sox2 and Nanog. Tfcp2l1 expression is lost during culture in normoxia, and its expression in hypoxia is regulated by Hif1α. Consistently, its overexpression in hypoxic levels increases the lifespan of MEFs and promotes the overexpression of stemness genes. ATAC-seq and Chip-seq experiments showed that Tfcp2l1 regulates genes that control proliferation and stemness such as Sox2, Sox9, Jarid2 and Ezh2. Additionally, Tfcp2l1 can replicate the hypoxic effect of increasing cellular reprogramming. Altogether, our data suggest that the activation of Tfcp2l1 by hypoxia contributes to immortalization prior to malignant transformation, facilitating tumorigenesis and dedifferentiation by regulating Sox2, Sox9, and Jarid2.

Effects of fermented soymilk with Lacticaseibacillus paracasei YIT 9029 on gut microbiota and defecation habits: a randomised, double-blind, placebo-controlled study

Previous studies have demonstrated that soymilk and Lacticaseibacillus paracasei YIT 9029 (strain Shirota: LcS) each beneficially affect the gut microbiota and defecation habits. To investigate the effects of daily consumption of fermented soymilk containing LcS (FSM), we conducted a randomised, double-blind, placebo-controlled study of 112 healthy Japanese adults with a low faecal Bifidobacterium count. They consumed 100 ml FSM or placebo (unfermented soymilk base) once daily for 4 weeks. Their gut microbiota was analysed by 16S rRNA gene amplicon sequencing and quantitative reverse transcription-polymerase chain reaction (PCR), and faecal short-chain fatty acids (SCFAs) and urinary putrefactive products were assessed during the pre- and post-consumption periods. Defecation habits were examined weekly using a subjective questionnaire. In the post-consumption period, living LcS were not detected in two subjects in the FSM group (n = 57) but were detected in one subject in the SM group (n = 55). The FSM group had a significantly higher number and relative abundance of faecal lactobacilli compared with the placebo group. The relative abundance of Bifidobacterium, alpha-diversity of microbiota, and concentrations of acetate and total SCFAs in faeces were significantly increased in the FSM group, although no significant differences were detected between the groups. The number of defecations and defecation days per week significantly increased in both groups. Subgroup analysis of 109 subjects, excluding 3 with inconsistent LcS detection (2 and 1 subjects in the FSM and SM groups, respectively), revealed that the FSM group (n = 55) had significantly greater increases in faecal acetate concentration compared with the SM group (n = 54) and significant upregulation of pathways related to energy production or glucose metabolism in the gut microbiota. These findings suggest that daily FSM consumption improves the gut microbiota and intestinal environment in healthy adults and may help to maintain health and prevent diseases. Registered at the University Hospital Medical Information Network (UMIN) clinical trials registry under: UMIN 000035612.

Acrylamide monomers in universal adhesives

OBJECTIVES

The mono-functional monomer 2-hydroxyethyl methacrylate (HEMA) is often added to universal adhesives (UAs) to improve surface wetting and prevent phase separation. Nevertheless, HEMA promotes water sorption and hydrolysis at adhesive interfaces, hereby affecting long-term bonding to dentin. This study investigated if two acrylamide monomers could replace HEMA in an UA formulation applied in etch-and-rinse (2E&R) and self-etch (1SE) bonding mode.

METHODS

Four experimental UAs were bonded to bur-cut dentin. In addition to 12 wt% 10-MDP, 25 wt% Bis-GMA and 10 wt% TEGDMA as common monomer composition, 20 %wt ethanol and 15 %wt water as solvent, and 3 wt% polymerization-related additives, the four formulations solely differed for either the acrylamide cross-linker monomer 'FAM-201' as TEGDMA alternative and HEMA replacement, the hydroxyethyl acrylamide monomer 'HEAA' as HEMA alternative, HEMA ('HEMA+'), or extra TEGDMA in a HEMA-free control ('HEMA-'), all added in a 15 wt% concentration. The split-tooth study design involved application in 2E&R mode on one tooth half versus 1SE mode on the corresponding half. Micro-tensile bond strength of half of the micro-specimens was measured upon 1-week distilled water storage ('immediate' 1w μTBS), with the other half measured after additional 6-month storage ('aged' 6 m μTBS). Statistics involved linear mixed-effects (LME) modelling (p < .05). Additionally, interfacial TEM characterization, thin-film (TF) XRD surface analysis, LogP determination, and a cytotoxicity assay were carried out.

RESULTS

FAM-201 revealed significantly higher μTBS than HEMA+ at 1w and 6 m when applied both in E&R and SE bonding modes. HEAA's μTBS was significantly lower than that of HEMA+ at 1w when applied in SE mode. TF-XRD and TEM revealed similar chemical and ultrastructural interfacial characterization, including stable 10-MDP_Ca salt nano-layering. FAM-201 was least cytotoxic and presented with an intermediary LogP, while HEAA presented with the highest LogP, indicating high hydrophilicity and water-sorption sensitivity.

SIGNIFICANCE

The acrylamide co-monomer FAM-201 could replace HEMA in an UA formulation, while HEAA not.

Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen

The KamLAND-Zen experiment has provided stringent constraints on the neutrinoless double-beta (0νββ) decay half-life in ^{136}Xe using a xenon-loaded liquid scintillator. We report an improved search using an upgraded detector with almost double the amount of xenon and an ultralow radioactivity container, corresponding to an exposure of 970 kg yr of ^{136}Xe. These new data provide valuable insight into backgrounds, especially from cosmic muon spallation of xenon, and have required the use of novel background rejection techniques. We obtain a lower limit for the 0νββ decay half-life of T_{1/2}^{0ν}>2.3×10^{26}  yr at 90% C.L., corresponding to upper limits on the effective Majorana neutrino mass of 36-156 meV using commonly adopted nuclear matrix element calculations.

Variable histopathology features of neuronal dyslamination in the cerebral neocortex adjacent to epilepsy-associated vascular malformations suggest complex pathogenesis of focal cortical dysplasia ILAE type IIIc

Focal cortical dysplasia type IIIc (FCD‐IIIc) is histopathologically defined by the International League Against Epilepsy's classification scheme as abnormal cortical organization adjacent to epilepsy‐associated vascular malformations (VM). However, the incidence of FCD‐IIIc, its pathogenesis, or association with the epileptogenic condition remains to be clarified. We reviewed a retrospective series of surgical brain specimens from 14 epilepsy patients with leptomeningeal angiomatosis of Sturge‐Weber syndrome (LMA‐SWS; n = 6), cerebral cavernous malformations (CCM; n = 7), and an arteriovenous malformation (AVM; n = 1) to assess the histopathological spectrum of FCD‐IIIc patterns in VM. FCD‐IIIc was observed in all cases of LMA‐SWS and was designated as cortical pseudolaminar sclerosis (CPLS). CPLS showed a common pattern of horizontally organized layer abnormalities, including neuronal cell loss and astrogliosis, either manifesting predominantly in cortical layer (L) 3 extending variably to deeper areas with or without further extension to L2 and/or L4. Another pattern was more localized, targeting mainly L4 with extension to L3 and/or L5. Abnormal cortical layering characterized by a fusion of L2 and L3 or L4–L6 was also noted in two LMA‐SWS cases and the AVM case. No horizontal or vertical lamination abnormalities were observed in the specimens adjacent to the CCM, despite the presence of vascular congestion and dilated parenchymal veins in all VM. These findings suggest that FCD‐IIIc depends on the type of the VM and developmental timing. We further conclude that FCD‐IIIc represents a secondary lesion acquired during pre‐ and/or perinatal development rather than following a pathomechanism independent of LMA‐SWS. Further studies will be necessary to address the selective vulnerability of the developing cerebral neocortex in LMA‐SWS, including genetic, encephaloclastic, hemodynamic, or metabolic events.

Touch-Cure Polymerization at the Composite Cement-Dentin Interface

Ceramic restorations are often adhesively luted onto the tooth prep. The so-called touch-cure concept was developed to yield optimum polymerization of composite cement at the restoration-cement-tooth interface for immediate bond stabilization. Although this touch cure is theorized to initiate polymerization at the interface when the accelerator in the primer makes contact with the cement, this process has not yet been proven. This study aimed to elucidate the mechanism of touch cure by measuring the degree of conversion (DC) of composite cement applied with or without an accelerator-containing tooth primer (TP) versus an accelerator-free primer using real-time Fourier-transform infrared spectroscopy (RT-FTIR) and attenuated total reflection (ATR)-FTIR. Interfacial bond strength was measured in shear mode, the accelerator composition confirmed by X-ray fluorescence analysis (XRF), and the interfacial interaction of TP and composite cement with dentin investigated by X-ray diffraction (XRD), focused-ion-beam scanning electron microscopy (FIB-SEM) with 3-dimensional interface reconstruction, and transmission electron microscopy (TEM). RT/ATR-FTIR revealed the significantly highest DC when the composite cement was applied with the accelerator-containing primer. XRF disclosed a vanadium compound as a novel chemical accelerator within TP, instead of a classic chemical curing initiator system, to set off touch cure as soon the cement contacts the previously applied primer. Although the TP contains the acidic functional monomer 10-MDP for adhesion to tooth tissue, touch cure using the accelerator-containing TP combined the fastest/highest DC with the highest bond strength. FIB-SEM and TEM confirmed the tight interfacial interaction at dentin with submicron hybridization along with stable 10-MDP also Ca-salt nanolayering.

Nano-Layering Adds Strength to the Adhesive Interface

X-ray diffraction (XRD) surface analysis and ultrastructural interfacial characterization using transmission electron microscopy (TEM) confirmed that the functional monomer 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) self-assembles into nano-layers at adhesive-tooth interfaces. Self-assembled nano-layering is thought to contribute to the durability of bonding to tooth dentin, although this has not been proven yet. In order to disclose this potential bond-durability contribution of nano-layering, we observed the 3-dimensional (3D) spreading of nano-layering by a series of focused-ion-beam (FIB) milled cross sections by scanning electron microscopy (FIB-SEM) and examined the mechanical properties of self-assembled nano-layering using scanning probe microscopy (SPM). A commercial 10-MDP-containing 3-step self-etch adhesive partially demineralized dentin up to submicron depth, forming a submicron hydroxyapatite-rich hybrid layer. TEM chemically and ultrastructurally confirmed the formation of interfacial nano-layering. FIB-SEM 3D reconstructions disclosed a 3D network of self-assembled nano-layering extending from the hybrid layer up to within the adjacent adhesive-resin layer. SPM revealed that nano-layering within the adhesive-resin layer possessed a higher elastic modulus than that of the surrounding adhesive resin, hereby suggesting that nano-layering contributes to the mechanical strength of adhesives like filler particles do. Nano-layering's 3D expanded structure is expected to strengthen the surrounding resin, as well to better interconnect the adhesive-resin layer to the hybrid layer. In conclusion, this exploratory study demonstrated that nano-layering constitutes a strong phase at the adhesive interface, which may contribute to the clinical longevity of the 10-MDP-based bond to dentin.

Purification of human iPSC-derived cardiomyocytes by HDAC inhibition through inducing apoptosis and cell arrest in non-cardiomyocytes

Background

Cell therapy is one of the most promising strategies for treatment of heart failure. During preparation of iPSC-derived cardiomyocytes for cells therapy, it is important to eliminate the presence of residual proliferative non-target cells in the preparation as these non-target cells could present the risk of tumorgenicity. To minimize the risk, selective and more precise purification process is necessary.

Purpose

We hypothesized that the differences in proliferative activity between cardiomyocytes and non-target cells might result in different sensitivities to the drugs targeting cell growth/survival. The aim of this study is to obtain compounds that eliminate non-cardiomyocytes selectively and to study the mechanism of action of these compounds.

Methods and results

We screened 314 small compounds using both iPSCs and sorted hiPSC-derived cardiomyocytes (hiPSC-CMs). We identified several compounds, which markedly decreased the cell numbers of iPSCs, but showed minimum effects on those of hiPSC-CMs. Among them, HDAC inhibitors were selected as the most promising candidates. We examined whether HDAC inhibitors could purify hiPSC-CMs containing non-cardiomyocytes populations, which were differentiated using the classical embryoid body (EB) method. As a result, HDAC inhibitors increased the purity of cardiomyocytes (up to 98%) by decreasing non-target cells such as smooth muscle cells, endothelial cells, and endodermal lineage cells. Moreover, we confirmed HDAC inhibitors could be used for purification of cardiomyocytes in monolayer differentiation protocol using GSK3β inhibitor and Wnt inhibitor. We measured the expression levels of mRNA and protein in iPSCs and hiPSC-CMs (EB method) treated with HDAC inhibitors. mRNA levels of CDKN1A (p21) and BAX were upregulated in iPSCs. Western blotting analyses revealed that HDAC inhibitors also induced the expression of p21 and the cleavage of Caspase3 in iPSCs.

Conclusions

Our result suggests that the inhibition of HDAC enables an efficient purification of hiPSC-CMs in multiple differentiation methods. Furthermore, our data indicate that HDAC inhibitors induce the apoptosis and cell cycle arrest in iPSCs but not hiPSC-CMs.

Figure 1

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Takeda Pharmaceutical Company Limited

Preclinical proof-of-concept study: antisense-mediated knockdown of CALM as a therapeutic strategy for calmodulinopathy

Background

Calmodulin (CaM) is a ubiquitous Ca2+ sensor molecule encoded by three distinct calmodulin genes, CALM1–3, and has an important role for cardiac ion channel function. Recently, heterozygous missense mutations in CALM genes were reported to cause a new category of life-threatening genetic arrhythmias such as long-QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardia (CPVT), which is called as “calmodulinopathy”. The patients with calmodulinopathy show poor prognosis and there is no effective treatment for them.

Purpose

Considering the dominant-negative effect of mutant calmodulin proteins produced by heterozygous missense mutations in CALMs, we aimed to prove the concept of antisense-based therapy to treat calmodulinopathy using human iPS cell-derived cardiomyocyte (hiPSC-CM) model.

Methods

We designed multiple locked nucleic acid (LNA) gapmer-antisense oligonucleotides (ASOs) targeting CALM2 and analyzed the silencing efficiency and toxicity in cultured cells to select the most potent ASO. Using CMs differentiated from hiPSCs which were generated form a 12-year-old boy with LQTS carrying a heterozygous CALM2-N98S mutation, CALM2 expression and action potentials (APs) were analyzed to evaluate the efficacy of ASOs.

Results

We identified several ASOs which reduced CALM2 expression without affecting cell viability in human cultured cells (HepG2) (ASO 50 nM, n=2; Figure 1A). Considering further experiments in vivo mouse model, we investigated the CALM2 silencing activity in mouse cultured cells (3T3-L1) without transfection (free-uptake) (ASO 1 μM, n=2; †ASOs have homologous sequence between human and mouse; Figure B). After free-uptake CALM2 silencing analysis in 3T3-L1 cells, we identified that ASO #2 has the most potent CALM2 silencing activity and low cytotoxicity (Figure 1B). ASO #2 effectively reduced CALM2 expression even in hiPSC-CMs (ASO(−): n=3, lipofection: n=4, free-uptake: n=3; P&lt;0.05; Figure 1C). In action potential recordings, we demonstrated that ASO #2 ameliorated prolonged AP durations (APD90) in N98S-hiPSC-CMs at 0.5 Hz pacing (ASO(−): 666±123 ms (n=7), lipofection: 329±21 ms (n=8), free-uptake: 388±34 ms (n=12); P&lt;0.05; Figure 1D).

Conclusion

Our results using patient-derived hiPSC-CM model suggest that ASO-based therapy might be a promising strategy for the treatment of calmodulinopathy.

Figure 1

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Nissan Chemical Corporation

Visceral fat accumulation and left atrial phasic function in the general population

Background

Obesity carries independent risk for incident atrial fibrillation (AF), although the impact of abdominal fat distribution on LA morphological and functional remodeling is not fully elucidated. Speckle-tracking echocardiography is a novel and sensitive tool that allows quantification and detection of subtle alterations in left atrial (LA) phasic function.

Purpose

This study aimed to investigate whether increased visceral adiposity is independently associated with impaired LA phasic function in a community-based cohort.

Methods

We included 527 participants without overt cardiac disease who underwent laboratory testing, abdominal computed tomographic examination and speckle-tracking echocardiography. Abdominal adiposity was quantitatively assessed as visceral fat area (VFA) and subcutaneous fat area (SFA) at the level of the umbilicus. Speckle-tracking echocardiography was performed to assess LA phasic function including reservoir, conduit and pump strain as well as left ventricular global longitudinal strain (LVGLS).

Results

Mean age was 57±10 years and 362 of the participants (69%) were men. LA reservoir and conduit strain were decreased according to the VFA quartiles (both p&lt;0.05), whereas there was no significant difference in LA volume index and LA pump strain. When stratified by SFA, there was no significant differences in LA volume index and all LA phasic strain across the quartiles. In multivariable analysis, VFA as continuous variable was significantly associated with LA conduit strain, independent of traditional cardiovascular risk factors, pertinent laboratory parameters and LV morphology and function including LVGLS (standardized b=−0.146, p=0.011). Representative cases are shown in the Figure.

Conclusion

In a sample of the general population, VFA accumulation was independently associated with worse LA conduit strain, which may be involved in the pathophysiological mechanism of obesity-related AF.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Yamauchi Susumu Scholarship for Cardiovascular Research

Obesity associated pro-fibrotic protein augments fibrosis in heart

 

Chronic sterile inflammation in visceral fat has causal roles for systemic metabolic disorders in obesity. Inflamed visceral adipose tissue secretes pro-inflammatory adipokines, and this contributes to tissue remodeling under a metabolically stressed condition. Various kinds of white adipokines are broadly studied, however, roles of brown adipose tissue (BAT) derived adipokines (BATokine) remain to be explored. In this project, we tried to characterize pathogenic role of BATokine in obesity related fibrotic disorders, especially focusing on heart failure with preserved ejection fraction (HFpEF). For this purpose, we analyzed two sets of DNA microarray data, and identified an obesity associated pro-fibrotic protein (OAFP) as a possible pathogenic BATokine. Our biobank studies showed OAFP increased in patients with diastolic dysfunction, and E/e' analyzed with cardiac echo increased in direct proportion to circulating OAFP level in humans. We generated dietary obese mice model, and found OAFP increased both in BAT and circulation. We generated a murine systemic or BAT specific OAFP knockout (KO) models, and found that obesity-induced diastolic dysfunction ameliorated in these models. Cardiac fibrosis was also suppressed by genetic depletion of OAFP. We found OAFP increased in circulation in aged humans and mice, and studies in chronologically aged mice showed this molecule increased in BAT with aging. Our results indicate that OAFP is secreted predominantly from BAT, and mediates pathogenic roles by augmenting cardiac fibrosis in dietary obesity or aging. Suppression of OAFP may become a therapy for HFpEF.

Funding Acknowledgement

Type of funding source: None

Sarcopenia-derived exosomal micro-RNA 16-5p exerts the cardio-repair disturbance via pro-apoptotic mechanism in myocardial infarction of mice

Background

Sarcopenia is a pathophysiological malfunction induced by skeletal muscle atrophy, and several studies reported an association between sarcopenia-induced cardiac cachexia and poor prognosis in heart disease. Since only a few established animal models are recently available, the underlying mechanism of disturbed cardiac repair accompanied with sarcopenia remains poorly understood.

Purpose

We hypothesized that specific microRNAs in sarcopenia-derived exosomes play crucial roles in disturbed cardiac repair with sarcopenia, and these microRNAs directly exacerbate cardiomyocyte injury following cardiac ischemia and reperfusion.

Methods

We developed a novel sarcopenia-induced cardiac repair disturbance mouse model that is induced by tail suspension (TS) 7 days after a 45-min coronary occlusion of cardiac ischemia and reperfusion (I/R). The reduction of the left ventricular ejection fraction (LVEF) after I/R was compared in mice with TS [I/R-TS(+), n=14] and without [I/R-TS(−), n=12] by echocardiography. To investigate the exosomal mechanism of cardiac repair disturbance, a comprehensive analysis of extracted exosomal microRNAs from mice serum was performed in the 2 groups at day 8. Then, we investigated the impact of the identified candidate microRNA in neonatal rat cardiomyocytes (NRVMs). After 4 days in primary culture, candidate microRNA was transfected into NRVMs under hypoxic culture conditions. TUNEL analysis and quantitative PCR analysis of apoptosis-related genes were performed on the NRVMs.

Results

At day 8 after I/R, the LVEF of I/R-TS(+) was not significantly ameliorated compared to that of I/R-TS(−) (ΔLVEF; 1.59±6.92 vs. 8.04±7.71% p=0.034). Four candidate microRNAs obtained from I/R mice serum were identified in the microRNA array analysis. The re-analysis of these candidate micro-RNAs using all I/R mice demonstrated that the level of mir-16-5p in I/R-TS(+) was raised by approximately nine-fold than that in I/R-TS(−) (9.67±13.35 vs. 0.99±1.41, p&lt;0.05). Next, an in vitro experimental model using a microRNA mimic revealed that apoptosis in NRVMs was greatly enhanced by the transfection of a mir-16-5p mimic in hypoxic culture conditions (mir-16-5p vs. control = 5.77±2.84 vs. 1.72±0.55%, p&lt;0.01). Furthermore, by qRT-PCR analysis, the expression of CASP3 and TRP53 were upregulated in NRVMs treated with a mir-16-5p mimic than in control NRVMs.

Conclusion

Myocardial I/R injury in sarcopenia ended in cardiac repair disturbance accompanying with the enhanced expression of exosomal-mir-16-5p. A pro-apoptotic effect of mir-16-5p may exacerbate myocardial I/R injury and thus can be a novel therapeutic target for cardiac repair disturbance in sarcopenia.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Japan Society for the Promotion of Science

The crucial roles of coagulation factors in inducing brown adipose tissue dysfunction and systemic metabolic disorder in obesity

 

The prevalence of obesity is increasing worldwide. Obese individuals are predisposed to cardio-metabolic disorders. Brown adipose tissue (BAT) is an active metabolic organ abundant with mitochondria, and studies suggest a potential role of BAT in the maintenance of metabolic health in rodents and humans. Metabolic stress causes BAT dysfunction, but the underlying mechanisms are largely unknown. Coagulation factor Xa (FXa) is critically involved in a coagulation cascade, and it is also known to mediate biological effects by the activation of protease-activated receptor (PAR)-signaling. Accumulating evidence shows that PAR1 contributes to tissue remodeling in cardiovascular system. Analyzing deposited microarray data, we found transcripts for coagulation factors including factor VII (F7), factor X (F10), and PAR1 receptor were increased in BAT from obese mice. Here we show a previously unknown role of FXa-PAR signaling in promoting BAT dysfunction and systemic metabolic disorder in a murine dietary obese model.

Imposing a high fat diet (HFD) on C57BL/6NCr mice led to a marked increase in tissue factor (TF), coagulation factor VII and FXa in BAT. TF-FVIIa (activated form of FVII)-FXa complex is known to activate PAR1, and we found a significant increase in PAR1 expression in BAT upon metabolic stress. Administration of a FXa inhibitor ameliorated BAT whitening, improved thermogenic response and systemic glucose intolerance upon dietary obesity. Fxa inhibition reduced reactive oxygen species (ROS) level in BAT. In contrast, administration of warfarin did not show any phenotype in BAT. BAT specific TF and PAR1 over-expression model showed significant whitening of this tissue, which was associated with systemic glucose intolerance. We generated BAT specific PAR1 KO mice. BAT-PAR1 KO mice exhibited re-browning of BAT along with reduced ROS level in this tissue. In BAT-PAR1 KO mice, glucose intolerance and thermogenic response under a metabolically stressed condition were ameliorated. In differentiated brown adipocytes, FXa markedly increased mitochondrial ROS and reduced mitochondrial membrane potential. Inhibition of PAR1 ameliorated FXa-induced mitochondrial ROS production and reduction in membrane potential. We also found that plasma FXa level did not increase in obese mice as well as in obese individuals. These results suggest the previously unknown role of coagulation systems in promoting BAT dysfunction, leading to systemic metabolic disorders. Maintenance of BAT homeostasis through the suppression of FXa-PAR1 signaling would become a new therapeutic target for obesity and diabetes.

Funding Acknowledgement

Type of funding source: None

Differential expression levels of CD151 enable enrichment of atrial cardiomyocytes derived from human induced-pluripotent stem cell

Introduction

Human iPSCs-derived cardiomyocytes (hiPSCs-CMs) are heterogeneous populations that contain ventricular-like CMs (VCMs), atrial-like CMs (ACMs) and pacemaker cells. Isolation of pure populations of each hiPSCs-CM subtype corresponding to the target regions of the heart enables effective drug screening process and stable engraftment of hiPSCs-CMs (e.g. ventricular cardiomyocytes without impurities).

Purpose

Atrial and ventricular cardiomyocytes develop from distinct mesoderm populations, and many of different genes are expressed between two subtypes. Since our method of cardiomyocytes differentiation from hiPSCs mimics in vivo cardiomyocytes development, we hypothesized that two subtypes could be separated by differentially expressed genes in hiPSCs-CMs differentiation process. In this study, we focused cell surface genes which are useful for analysis by flow cytometry, and then identified cell surface marker that can distinguish atrial and ventricular cardiomyocytes from hiPSCs-CMs.

Methods

We performed an antibody-based screening using hiPSCs-CMs induced under atrial induction condition (AIC) and ventricular induction condition (VIC) by flow cytometry. To identify cell surface markers which enable discrimination of cardiac subtypes, we isolated the cell populations using the antibodies against the cell surface markers. Quantitative PCR was performed to analyze expression levels of subtype-specific genes in sorted cells. We confirmed subtype classification of cells using patch-clamp method.

Results

We identified CD151 as a novel candidate of atrial/ventricular selectable marker. The expression level of CD151 was low in most hiPSCs-CMs under AIC. In these cells, CD151-low cells highly expressed atrial genes compared to CD151-high cells. In contrast, the expression level of CD151 was high in most hiPSCs-CMs under VIC. In these cells, CD151-high cells highly expressed ventricular genes compared to CD151-low cells. Furthermore, we investigated the electrophysiological properties of CD151-high and -low cells using patch-clamp experiments. As expected, the cells showing atrial type action potential were enriched in AIC with low expression of CD151 (n=17). On the other hand, CD151-high cells (n=16) contained no atrial CMs, but mostly nodal like cells. In addition, CD151-low cells in AIC were affected with action potential duration by exposure of atrial specific channel blocker (4-aminopyridine) and activator (carbachol). In VIC, CD151-high cells (n=16) demonstrated ventricular type action potential property compared to CD151-low cells (n=21).

Conclusion

These results suggest that CD151 is a useful marker which can enrich ACMs from hiPSCs-CMs. Because these enriched ACMs are uniform population, it may be appropriate for atrial-selective drug screening. Additionally, this marker can reduce contaminated ACMs from hiPSCs-CMs cultured in VIC.

Action potential of CD151-high/low CMs

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Takeda pharmaceutical company limited, Japan society for the promotion of science(JSPS) KAKENHI

Carotid intima-media thickness and subclinical left heart dysfunction in the general population

Background

Although carotid intima-media thickness (IMT) is an established marker of atherosclerosis and carries independent risk for cardiovascular disease, its possible association with subclinical cardiac dysfunction has not been extensively evaluated. Left ventricular global longitudinal strain (LVGLS) and peak left atrial longitudinal systolic strain (PALS) can detect subclinical left heart dysfunction.

Purpose

This study aimed to investigate the association between carotid IMT and subclinical left heart dysfunction in a large sample of the general population without overt cardiac disease.

Methods

We examined 1,161 participants who underwent extensive cardiovascular examination. Ultrasonography of common carotid artery was performed for the measurement of maximal carotid IMT. LVGLS and PALS were assessed by 2-dimensional speckle-tracking echocardiography.

Results

Mean age was 62±12 years, and 56% were male. The prevalence of abnormal LVGLS (&gt;−18.6%) and PALS (&lt;31.4%) was greatest in the upper quartile of carotid IMT (both p&lt;0.001; Figure). In multivariable analyses, carotid IMT was associated with abnormal LVGLS (adjusted odds ratio = 1.33 per 1SD increase of IMT, p=0.003) as well as PALS (adjusted odds ratio = 1.33 per 1SD increase of IMT, p=0.005) independent of traditional cardiovascular risk factors, echocardiographic parameters including LV ejection fraction, LV mass index and diastolic dysfunction, and pertinent laboratory parameters. The independent association between carotid IMT and PALS persisted even after adjustment for LVGLS. When carotid IMT was examined as a categorical variable, the upper quartile of carotid IMT carried a significant risk of abnormal LVGLS and PALS in a fully-adjusted model including echocardiographic and laboratory parameters (adjusted odds ratio 2.27 and 3.03 vs. lower quartile, both p&lt;0.01).

Conclusion

Participants with increased IMT had significantly impaired LV and LA function in an unselected community-based cohort. This association may be involved in the higher incidence of cardiovascular disease in individuals with increased carotid IMT.

Funding Acknowledgement

Type of funding source: None