Although elevated soluble uric acid (SUA) levels enhance the production of IL-1β in macrophages stimulated with monosodium urate (MSU) crystals, the underlying mechanism remains unelucidated. The aim of this study was to examine the effects of SUA on inflammatory response-related gene expression in lipopolysaccharide-primed and MSU crystal-stimulated macrophages using mouse macrophage-like J774.1 cells. Differential gene expression in SUA-pretreated and untreated group cells was analyzed by RNA sequencing and quantitative reverse transcription-polymerase chain reaction. SUA upregulated the genes related to pro-inflammatory reactions and downregulated those related to anti-inflammatory reactions. SUA also upregulated M1 pro-inflammatory macrophage-related genes and enhanced mRNA expression of CD44 responsible for phagocytosis of MSU crystals. These results suggest that SUA enhances gouty inflammation via promoting the expression of genes related to pro-inflammatory reactions, polarization toward the M1 phenotype, and MSU crystal phagocytosis in macrophages. Enhanced expression of the transcription factor genes Nfkb1 and Stat1 may underlie the SUA-induced M1 polarization and resulting enhancement of inflammasome activation and IL-1β transcription.

It remains to be elucidated whether Ca2+ antagonists induce pharmacological preconditioning to protect the heart against ischemia/reperfusion injury. The aim of this study was to determine whether and how pretreatment with a Ca2+ antagonist, azelnidipine, could protect cardiomyocytes against hypoxia/reoxygenation (H/R) injury in vitro. Using HL-1 cardiomyocytes, we studied effects of azelnidipine on NO synthase (NOS) expression, NO production, cell death and apoptosis during H/R. Action potential durations (APDs) were determined by the whole-cell patch-clamp technique. Azelnidipine enhanced endothelial NOS phosphorylation and NO production in HL-1 cells under normoxia, which was abolished by a heat shock protein 90 inhibitor, geldanamycin, and an antioxidant, N-acetylcysteine. Pretreatment with azelnidipine reduced cell death and shortened APDs during H/R. These effects of azelnidipine were diminished by a NOS inhibitor, L-NAME, but were influenced by neither a T-type Ca2+ channel inhibitor, NiCl2, nor a N-type Ca2+ channel inhibitor, ω-conotoxin. The azelnidipine-induced reduction in cell death was not significantly enhanced by either additional azelnidipine treatment during H/R or increasing extracellular Ca2+ concentrations. RNA sequence (RNA-seq) data indicated that azelnidipine-induced attenuation of cell death, which depended on enhanced NO production, did not involve any significant modifications of gene expression responsible for the NO/cGMP/PKG pathway. We conclude that pretreatment with azelnidipine protects HL-1 cardiomyocytes against H/R injury via NO-dependent APD shortening and L-type Ca2+ channel blockade independently of effects on gene expression.

The differentiation of neural crest (NC) cells into various cell lineages contributes to the formation of many organs, including the thymus. In this study, we explored the role of NC cells in thymic T cell development. In double-transgenic mice expressing NC-specific Cre and the Cre-driven diphtheria toxin receptor, plasma noradrenaline and adrenaline levels were significantly reduced, as were thymic T cell progenitors, when NC-derived cells were ablated with short-term administration of diphtheria toxin. Additionally, yellow fluorescent protein+ NC-derived mesenchymal cells, perivascular cells, and tyrosine hydroxylase+ sympathetic nerves in the thymus significantly decreased. Furthermore, i.p. administration of 6-hydroxydopamine, a known neurotoxin for noradrenergic neurons, resulted in a significant decrease in thymic tyrosine hydroxylase+ nerves, a phenotype similar to that of depleted NC-derived cells, whereas administration of a noradrenaline precursor for ablating NC-derived cells or sympathetic nerves rarely rescued this phenotype. To clarify the role of NC-derived cells in the adult thymus, we transplanted thymus into the renal capsules of wild-type mice and observed abnormal T cell development in lethally irradiated thymus with ablation of NC-derived cells or sympathetic nerves, suggesting that NC-derived cells inside and outside of the thymus contribute to T cell development. In particular, the ablation of NC-derived mesenchymal cells in the thymus decreases the number of thymocytes and T cell progenitors. Overall, ablation of NC-derived cells, including sympathetic nerves, in the thymus leads to abnormal T cell development in part by lowering plasma noradrenalin levels. This study reveals that NC-derived cells including mesenchymal cells and sympathetic nerves within thymus regulate T cell development.

AbstractPlatelet-rich plasma (PRP) and adipose-derived stem cells (ADSCs) are known to secrete angiogenic factors that contribute to the treatment of intractable ulcers. The combination of PRP and ADSCs may enhance their angiogenic effects. However, it remains unclear whether treatment of ADSCs with PRP influences angiogenesis. We studied whether the conditioned medium from PRP-treated ADSCs under hypoxic conditions exerts angiogenic effects. Although PRP stimulated the proliferation of ADSCs obtained from rats, it decreased the mRNA levels of vascular endothelial growth factor, hepatocyte growth factor, and TGF-β1, but not of basic fibroblast growth factor, under hypoxia. The conditioned medium of PRP-treated ADSCs inhibited endothelial nitric oxide synthase phosphorylation, decreased NO production, and suppressed tube formation in human umbilical vein endothelial cells. Transplantation of ADSCs alone increased both blood flow and capillary density of the ischemic limb; however, its combination with PRP did not further improve blood flow or capillary density. This suggests that both conditioned medium of ADSCs treated with PRP and combination of PRP with ADSCs transplantation may attenuate the phosphorylation of endothelial nitric oxide synthase and angiogenesis.

BackgroundCardiomyocytes derived from human iPS cells (hiPSCs) include cells showing SAN- and non-SAN-type spontaneous APs. ObjectivesTo examine whether the deep learning technology could identify hiPSC-derived SAN-like cells showing SAN-type-APs by their shape. MethodsWe acquired phase-contrast images for hiPSC-derived SHOX2/HCN4 double-positive SAN-like and non-SAN-like cells and made a VGG16-based CNN model to classify an input image as SAN-like or non-SAN-like cell, compared to human discriminability. ResultsAll parameter values such as accuracy, recall, specificity, and precision obtained from the trained CNN model were higher than those of human classification. ConclusionsDeep learning technology could identify hiPSC-derived SAN-like cells with considerable accuracy.

Soluble uric acid (UA) absorbed by cells through UA transporters (UATs) accumulates intracellularly, activates the NLRP3 inflammasome and thereby increases IL-1β secretion. ABCG2 transporter excludes intracellular UA. However, it remains unknown whether ABCG2 inhibition leads to intracellular accumulation of UA and increases IL-1β production. In this study, we examined whether genetic and pharmacological inhibition of ABCG2 could increase IL-1β production in mouse macrophage-like J774.1 cells especially under hyperuricemic conditions. We determined mRNA and protein levels of pro-IL-1β, mature IL-1β, caspase-1 and several UATs in culture supernatants and lysates of J774.1 cells with or without soluble UA pretreatment. Knockdown experiments using an shRNA against ABCG2 and pharmacological experiments with an ABCG2 inhibitor were conducted. Extracellularly applied soluble UA increased protein levels of pro-IL-1β, mature IL-1β and caspase-1 in the culture supernatant from lipopolysaccharide (LPS)-primed and monosodium urate crystal (MSU)-stimulated J774.1 cells. J774.1 cells expressed UATs of ABCG2, GLUT9 and MRP4, and shRNA knockdown of ABCG2 increased protein levels of pro-IL-1β and mature IL-1β in the culture supernatant. Soluble UA increased mRNA and protein levels of ABCG2 in J774.1 cells without either LPS or MSU treatment. An ABCG2 inhibitor, febuxostat, but not a urate reabsorption inhibitor, dotinurad, enhanced IL-1β production in cells pretreated with soluble UA. In conclusion, genetic and pharmacological inhibition of ABCG2 enhanced IL-1β production especially under hyperuricemic conditions by increasing intracellularly accumulated soluble UA that activates the NLRP3 inflammasome and pro-IL-1β transcription in macrophage-like J774.1 cells.

BACKGROUND:Gout is usually found in patients with atrial fibrillation (AF). K+ efflux is a common trigger of NLRP3 inflammasome activation which is involved in the pathogenesis of AF. We investigated the role of the K+ channel Kv1.5 in monosodium urate crystal (MSU)-induced activation of the NLRP3 inflammasome and electrical remodeling in mouse and human macrophages J774.1 and THP-1, and mouse atrial myocytes HL-1.METHODS AND RESULTS:Macrophages, primed with lipopolysaccharide (LPS), were stimulated by MSU. HL-1 cells were incubated with the conditioned medium (CM) from MSU-stimulated macrophages. Western blot, ELISA and patch clamp were used. MSU induced caspase-1 expression in LPS-primed J774.1 cells and IL-1β secretion, suggesting NLRP3 inflammasome activation. A selective Kv1.5 inhibitor, diphenyl phosphine oxide-1 (DPO-1), and siRNAs against Kv1.5 suppressed the levels of caspase-1 and IL-1β. MSU reduced intracellular K+ concentration which was prevented by DPO-1 and siRNAs against Kv1.5. MSU increased expression of Hsp70, and Kv1.5 on the plasma membrane. siRNAs against Hsp70 were suppressed but heat shock increased the expression of Hsp70, caspase-1, IL-1β, and Kv1.5 in MSU-stimulated J774.1 cells. The CM from MSU-stimulated macrophages enhanced the expression of caspase-1, IL-1β and Kv1.5 with increased Kv1.5-mediated currents that shortened action potential duration in HL-1 cells. These responses were abolished by DPO-1 and a siRNA against Kv1.5.CONCLUSIONS:Kv1.5 regulates MSU-induced activation of NLRP3 inflammasome in macrophages. MSUrelated activation of NLRP3 inflammasome and electrical remodeling in HL-1 cells are via macrophages. Kv1.5 may have therapeutic value for diseases related to gout-induced activation of the NLRP3 inflammsome, including AF.

IntroductionDysfunction of the sinoatrial node (SAN) cells causes arrhythmias, and many patients require artificial cardiac pacemaker implantation. However, the mechanism of impaired SAN automaticity remains unknown, and the generation of human SAN cells in vitro may provide a platform for understanding the pathogenesis of SAN dysfunction. The short stature homeobox 2 (SHOX2) and hyperpolarization-activated cyclic nucleotide-gated cation channel 4 (HCN4) genes are specifically expressed in SAN cells and are important for SAN development and automaticity. In this study, we aimed to purify and characterize human SAN-like cells in vitro, using HCN4 and SHOX2 as SAN markers.MethodsWe developed an HCN4-EGFP/SHOX2-mCherry dual reporter cell line derived from human induced pluripotent stem cells (hiPSCs), and HCN4 and SHOX2 gene expressions were visualized using the fluorescent proteins EGFP and mCherry, respectively. The dual reporter cell line was established using an HCN4-EGFP bacterial artificial chromosome-based semi-knock-in system and a CRISPR-Cas9-dependent knock-in system with a SHOX2-mCherry targeting vector. Flow cytometry, RT-PCR, and whole-cell patch-clamp analyses were performed to identify SAN-like cells.ResultsFlow cytometry analysis and cell sorting isolated HCN4-EGFP single-positive (HCN4(+)/SHOX2(-)) and HCN4-EGFP/SHOX2-mCherry double-positive (HCN4(+)/SHOX2(+)) cells. RT-PCR analyses showed that SAN-related genes were enriched within the HCN4(+)/SHOX2(+) cells. Further, electrophysiological analyses showed that approximately 70% of the HCN4(+)/SHOX2(+) cells exhibited SAN-like electrophysiological characteristics, as defined by the action potential parameters of the maximum upstroke velocity and action potential duration.ConclusionsThe HCN4-EGFP/SHOX2-mCherry dual reporter hiPSC system developed in this study enabled the enrichment of SAN-like cells within a mixed HCN4(+)/SHOX2(+) population of differentiating cardiac cells. This novel cell line is useful for the further enrichment of human SAN-like cells. It may contribute to regenerative medicine, for example, biological pacemakers, as well as testing for cardiotoxic and chronotropic actions of novel drug candidates.

The tooth is mainly composed of dentin and enamel. Identification of dentin-producing odontoblasts and enamel-producing ameloblasts using reporter techniques is useful to study tooth development and regeneration with tissue engineering. Ameloblasts express Amelogenin, Ameloblastin, Enamelin, and Amelotin, whereas odontoblasts express Dentin sialophosphoprotein ( Dspp) and Dentin matrix protein1 ( Dmp1). Although there are several transgenic lines using promoter elements or bacterial artificial chromosomes (BACs) to label odontoblasts and ameloblasts, there is a possibility that the expression patterns vary from the endogenous genes. Here, we established 2 lines of mice where tdTomato was knocked into the second exon of X-chromosomal Amelogenin ( Amelx), and green fluorescent protein (GFP) was knocked into the second exon of Dspp. tdTomato and GFP were highly expressed on secretory ameloblasts and secretory and fully differentiated odontoblasts, respectively. In addition, DSPP and AMELX were not produced in the dentin matrix and enamel matrix of Dspp GFP/GFP and Amelx tdTomato male mice (as representative of Amelx tdTomato/Y hemizygous male mice), respectively. Moreover, micro–computed tomography analysis of Amelx tdTomato male mice revealed a notable reduction in enamel volume but increased dentin mineral density. Dspp GFP/GFP mice had reduced dentin mineral density. To identify odontoblasts and ameloblasts from developing tooth, we examined the expression of mesenchymal cell surface molecules CD90, CD166 and epithelial cell surface molecules CD49f, Epcam1 with fluorescence on odontoblasts and ameloblasts in these mice. We found that GFP + odontoblasts and tdTomato + ameloblasts in tooth germ from 0.5-d-old Dspp GFP/+ mice and Amelx tdTomato male mice were enriched in CD45 − /Ter119 − /Epcam1 − /CD90 + /Integrin α4 + cell fractions and CD45 − /Ter119 − /Epcam1 + /CD49f + /CD147 + cell fractions, respectively. By using antibodies against mesenchymal and epithelial cell surface molecules and fluorescence, we can easily distinguish odontoblasts from ameloblasts and isolate each cell for further studies. These mice would serve as useful models for tooth development and regeneration as well as provide concurrent observation for the differentiation processes of odontoblasts and ameloblasts in vivo and in vitro.

BACKGROUND:Although adipose-derived stem cell (ADSC) sheets improve the cardiac function after myocardial infarction (MI), underlying mechanisms remain to be elucidated. The aim of this study was to determine the fate of transplanted ADSC sheets and candidate angiogenic factors released from ADSCs for their cardiac protective actions. METHODS AND RESULTS:MI was induced by ligation of the left anterior descending coronary artery. Sheets of transgenic (Tg)-ADSCs expressing green fluorescence protein (GFP) and luciferase or wild-type (WT)-ADSCs were transplanted 1 week after MI. Both WT- and Tg-ADSC sheets improved cardiac functions evaluated by echocardiography at 3 and 5 weeks after MI. Histological examination at 5 weeks after MI demonstrated that either sheet suppressed fibrosis and increased vasculogenesis. Luciferase signals from Tg-ADSC sheets were detected at 1 and 2 weeks, but not at 4 weeks, after transplantation. RNA sequencing of PKH (yellow-orange fluorescent dye with long aliphatic tails)-labeled Tg-ADSCs identified mRNAs of 4 molecules related to angiogenesis, including those of Esm1 and Stc1 that increased under hypoxia. Administration of Esm1 or Stc1 promoted tube formation by human umbilical vein endothelial cells. CONCLUSIONS:ADSC sheets improved cardiac contractile functions after MI by suppressing cardiac fibrosis and enhancing neovascularization. Transplanted ADSCs existed for >2 weeks on MI hearts and produced the angiogenic factors Esm1 and Stc1, which may improve cardiac functions after MI.

Cell-based therapy using adipose-derived stem cells (ADSCs) has emerged as a novel therapeutic approach to treat heart failure after myocardial infarction (MI). The purpose of this study was to determine whether inhibition of α1-adrenergic receptors (α1-ARs) in ADSCs attenuates ADSC sheet-induced improvements in cardiac functions and inhibition of remodeling after MI. ADSCs were isolated from fat tissues of Lewis rats. In in vitro studies using cultured ADSCs, we determined the mRNA levels of vascular endothelial growth factor (VEGF)-A and α1-AR under normoxia or hypoxia and the effects of norepinephrine and an α1-blocker, doxazosin, on the mRNA levels of angiogenic factors. Hypoxia increased α1-AR and VEGF mRNA levels in ADSCs. Norepinephrine further increased VEGF mRNA expression under hypoxia; this effect was abolished by doxazosin. Tube formation of human umbilical vein endothelial cells was promoted by conditioned media of ADSCs treated with the α1 stimulant phenylephrine under hypoxia but not by those of ADSCs pretreated with phenylephrine plus doxazosin. In in vivo studies using rats with MI, transplanted ADSC sheets improved cardiac functions, facilitated neovascularization, and suppressed fibrosis after MI. These effects were abolished by doxazosin treatment. Pathway analysis from RNA sequencing data predicted significant upregulation of α1-AR mRNA expression in transplanted ADSC sheets and the involvement of α1-ARs in angiogenesis through VEGF. In conclusion, doxazosin abolished the beneficial effects of ADSC sheets on rat MI hearts as well as the enhancing effect of norepinephrine on VEGF expression in ADSCs, indicating that ADSC sheets promote angiogenesis and prevent cardiac dysfunction and remodeling after MI via their α1-ARs.

Background: Monocarboxylate transporter 9 (MCT9), an orphan transporter member of the solute carrier family 16 (SLC16), possibly reabsorbs uric acid in the renal tubule and has been suggested by genome-wide association studies to be involved in the development of hyperuricemia and gout. In this study we investigated the mechanisms regulating the expression of human (h) MCT9, its degradation, and physiological functions. Methods and Results: hMCT9-FLAG was stably expressed in HEK293 cells and its degradation, intracellular localization, and urate uptake activities were assessed by pulse-chase analysis, immunofluorescence, and [14C]-urate uptake experiments, respectively. hMCT9-FLAG was localized on the plasma membrane as well as in the endoplasmic reticulum and Golgi apparatus. The proteasome inhibitors MG132 and lactacystine increased levels of hMCT9-FLAG protein expression with enhanced ubiquitination, prolonged their half-life, and decreased [14C]-urate uptake. [14C]-urate uptake was increased by both heat shock (HS) and the HS protein inducer geranylgeranylacetone (GGA). Both HS and GGA restored the [14C]-urate uptake impaired by MG132. Conclusions: hMCT9 does transport urate and is degraded by a proteasome, inhibition of which reduces hMCT9 expression on the cell membrane and urate uptake. HS enhanced urate uptake through hMCT9.

Background：When macrophages are primed by lipopolysaccharides, mono sodium urate (MSU) crystals activate NLRP3 inflammasomes and promote IL-1β and IL-18 production after phagocytosis of MSU. It was previously reported that anti-IL-1β antibodies suppress symptoms of gout and the occurrence of cardiovascular disease. Thus, inhibition of NLRP3 inflammasomes, which produce IL-1β and IL-18, may be a novel therapeutic strategy against these diseases. Purpose：To reveal the effects of dotinurad, a selective urate reabsorption inhibitor, and other uric acid lowering agents on MSU crystal-induced activation of NLRP3 inflammasomes in macrophages. Methods：Activity of NLRP3 inflammasomes in J774 mouse macrophages was evaluated by quantifying secreted caspase-1 and IL-1β using a western blot and ELISA in both the absence and presence of dotinurad or other uric acid lowering agents. Results：MSU increased protein levels of caspase-1 and IL-1β. This effect was inhibited by a clinical concentration of dotinurad. Neither febuxostat nor allopurinol influenced the levels of caspase-1 and IL-1β, whereas benzbromarone decreased their levels. The inhibitory effects of dotinurad and other uric acid lowering agents on secretions of IL-1β from the macrophages were confirmed by ELISA. Conclusion：Dotinurad, a selective urate reabsorption inhibitor, suppresses MSU-induced activation of NLRP3 inflammasomes in macrophages.

Myocardial ischemia/reperfusion injury worsens in the absence of nitric oxide synthase (NOS). Cilnidipine, a Ca2+ channel blocker, has been reported to activate endothelial NOS (eNOS) and increases nitric oxide (NO) in vascular endothelial cells. We examined whether pretreatment with cilnidipine could attenuate cardiac cell deaths including apoptosis caused by hypoxia/reoxygenation (H/R) injury. HL-1 mouse atrial myocytes as well as H9c2 rat ventricular cells were exposed to H/R, and cell viability was evaluated by an autoanalyzer and flow cytometry; eNOS expression, NO production, and electrophysiological properties were also evaluated by western blotting, colorimetry, and patch clamping, respectively, in the absence and presence of cilnidipine. Cilnidipine enhanced phosphorylation of eNOS and NO production in a concentration-dependent manner, which was abolished by siRNAs against eNOS or an Hsp90 inhibitor, geldanamycin. Pretreatment with cilnidipine attenuated cell deaths including apoptosis during H/R; this effect was reproduced by an NO donor and a xanthine oxidase inhibitor. The NOS inhibitor L-NAME abolished the protective action of cilnidipine. Pretreatment with cilnidipine also attenuated H9c2 cell death during H/R. Additional cilnidipine treatment during H/R did not significantly enhance its protective action. There was no significant difference in the protective effect of cilnidipine under normal and high Ca2+ conditions. Action potential duration (APD) of HL-1 cells was shortened by cilnidipine, with this shortening augmented after H/R. L-NAME attenuated the APD shortening caused by cilnidipine. These findings indicate that cilnidipine enhances NO production, shortens APD in part by L-type Ca2+ channel block, and thereby prevents HL-1 cell deaths during H/R.

Background: Treatment of myocardial infarction (MI) includes inhibition of the sympathetic nervous system (SNS). Cell-based therapy using adipose-derived stem cells (ASCs) has emerged as a novel therapeutic approach to treat heart failure in MI. The purpose of this study was to determine whether a combination of ASC transplantation and SNS inhibition synergistically improves cardiac functions after MI. Methods and Results: ASCs were isolated from fat tissues of Lewis rats. In in vitro studies using cultured ASC cells, mRNA levels of angiogenic factors under normoxia or hypoxia, and the effects of norepinephrine and a beta-blocker, carvedilol, on the mRNA levels were determined. Hypoxia increased vascular endothelial growth factor (VEGF) mRNA in ASCs. Norepinephrine further increased VEGF mRNA; this effect was unaffected by carvedilol. VEGF promoted VEGF receptor phosphorylation and tube formation of human umbilical vein endothelial cells, which were inhibited by carvedilol. In in vivo studies using a rat MI model, transplanted ASC sheets improved contractile functions of MI hearts; they also facilitated neovascularization and suppressed fibrosis after MI. These beneficial effects of ASC sheets were abolished by carvedilol. The effects of ASC sheets and carvedilol on MI heart functions were confirmed by Langendorff perfusion experiments using isolated hearts. Conclusions: ASC sheets prevented cardiac dysfunctions and remodeling after MI in a rat model via VEGF secretion. Inhibition of VEGF effects by carvedilol abolished their beneficial effects.

Introduction: Human induced pluripotent stem cells (hiPSCs) harboring cardiac myosin heavy chain 6 promoter can differentiate into functional cardiomyocytes called "iCell cardiomyocytes" under blasticidin treatment condition. While iCell cardiomyocytes are expected to be used for predicting cardiotoxicity of drugs, their responses to antiarrhythmic agents remain to be elucidated. We first examined electrophysiological properties of iCell cardiomyocytes and mRNA levels of ion channels and Ca handling proteins, and then evaluated effects of class I antiarrhythmic agents on their Na+ and Ca2+ currents. Methods: iCell cardiomyocytes were cultured for 8-14 days (38-44 days after inducing their differentiation), according to the manufacturer's protocol. We determined their action potentials (APs) and sarcolemmal ionic currents using whole-cell patch clamp techniques, and also mRNA levels of ion channels and Ca handling proteins by RT-PCR. Effects of three class I antiarrhythmic agents, pirmenol, pilsicainide and mexiletine, on Na+ channel current (I-Na) and L-type Ca2+ channel current (I-CaL) were evaluated by the whole-cell patch clamp. Results: iCell cardiomyocytes revealed sinoatrial node-type (18%), atrial-type (18%) and ventricular-type (64%) spontaneous APs. The maximum peak amplitudes of I-Na, I-CaL and rapidly-activating delayed-rectifier K+ channel current were -62.7 +/- 13.7, -8.1 +/- 0.7, and 3.0 +/- 1.0 pA/pF, respectively. The hyperpolarization-activated cation channel and inward-rectifier K+ channel currents were observed, whereas the T-type Ca2+ channel or slowly-activating delayed-rectifier K + channel current was not detectable. mRNAs of Nav1.5, Cav1.2, Kir2.1, HCN4, KvLQT1, hERG and SERCA2 were detected, while that of HCN1, minK or MiRP was not. The class Ia antiarrhythmic agent pirmenol and class Ic agent pilsicainide blocked I-Na in a concentration-dependent manner with IC50 of 0.87 +/- 0.37 and 0.88 +/- 0.16 mu M, respectively; the class lb agent mexiletine revealed weak I-Na block with a higher IC50 of 30.0 +/- 3.0 mu M. Pirmenol, pilsicainide and mexiletine blocked I-CaL with IC50 of 2.00 +/- 0.39, 7.7 +/- 2.5 and 5.0 +/- 0.1 mu M, respectively. Conclusions: In iCell cardiomyocytes, I-Na was blocked by the class Ia and Ic antiarrhythmic agents and I-CaL was blocked by all the class I agents within the ranges of clinical concentrations, suggesting their cardiotoxicity. (C) 2019, The Japanese Society for Regenerative Medicine. Production and hosting by Elsevier B.V.

BACKGROUND Intracellular uric acid is known to increase the protein level and channel current of atrial Kv1.5; however, mechanisms of the uric acid-induced enhancement of Kv1.5 expression remain unclear. Methods and Results: The effects of uric acid on mRNA and protein levels of Kv1.5, as well as those of Akt, HSF1 and Hsp70, in HL-1 cardiomyocytes were studied by using qRT-PCR and Western blotting. The uptake of uric acid was measured using radio-labeled uric acid. The Kv1.5-mediated channel current was also measured by using patch clamp techniques. Uric acid up-taken by HL-1 cells significantly increased the level of Kv1.5 proteins in a concentration-dependent manner, with this increase abolished by an uric acid transporter inhibitor. Uric acid slowed degradation of Kv1.5 proteins without altering its mRNA level. Uric acid enhanced phosphorylation of Akt and HSF1, and thereby increased both transcription and translation of Hsp70; these effects were abolished by a PI3K inhibitor. Hsp70 knockdown abolished the uric acid-induced increases of Kv1.5 proteins and channel currents. CONCLUSIONS Intracellular uric acid could stabilize Kv1.5 proteins through phosphorylation of Akt and HSF1 leading to enhanced expression of Hsp70.

Humidified incubators are widely used for culturing human embryos. However, the use of non-humidified benchtop incubators is becoming more common due to their smaller size and lower risk of fungal contamination. We previously reported that the osmotic pressure of culture media increased more than 20 mOsm/kg after continuous culture for five days in non-humidified incubators. Microdrops of culture medium are typically covered with mineral oil, which prevents changes in the medium's osmotic pressure, pH and temperature. Although several types of mineral oils are commercially available, it is unknown how the different types affect culture conditions. In this study, we examined how different mineral oil viscosities influenced the osmotic pressure of culture media in non-humidified incubators. Basic Clinical Study. We prepared 18 culture dishes containing six 50-μl microdrops of single-step medium (265 ± 10 mOsm/kg). Dishes were divided into three groups: A, light oil (10.8 mPa/sec at 37°C); B, heavy oil (36.5 mPa/sec at 37°C); and C, washed oil (10.4 mPa/sec at 37°C), and placed in a non-humidified benchtop incubator for six days. The osmotic pressure of one dish per group was measured daily using an osmometer. Student t-tests were used for statistical analyses. The osmotic values for each group are expressed as the mean ± S.D. In group A, the osmotic pressure increased from 268.4 ± 0.5 mOsm/kg (day 0) to 280.5 ± 0.5 mOsm/kg (day 3), and then 300.7 ± 2.4 mOsm/kg (day 6). The osmotic pressure in group B rose from 267.6 ± 0.5 mOsm/kg (day 0) to 275.6 ± 1.1 mOsm/kg (day 3), and then 286.8 ± 1.3 mOsm/kg (day 6). As with group B, the osmotic pressure in group C elevated from 267.6 ± 0.5 mOsm/kg (day 0) to 276.8 ± 0.8 mOsm/kg (day 3), and then 287.8 ± 0.4 mOsm/kg (day 6). These results showed that the osmotic pressure of microdrops covered by light oil significantly increased on day 3 onwards compared to that of microdrops covered by heavy oil (P < 0.01). Elevations in osmotic pressure are minimized by using heavy or washed mineral oils. Low-viscosity mineral oil significantly increased the osmotic pressure of culture medium after three days in a non-humidified incubator. However, our results also showed that the osmotic pressure of culture media will inevitably increase in non-humidified incubators regardless of the viscosity of the mineral oil. Therefore, depending on the types of mineral oil, culture media, culture period and incubators used, it may be possible for the osmotic pressure of culture media to exceed the optimal culture environment threshold for human embryos. Although in vitro culture is essential for ART programs, this system is unstable and insufficient compared to the in vivo situation. To more closely align the ART in vitro culture environment to that found in vivo, we must focus on optimizing the materials available to us.

Background：Activation of angiotensin receptor type1 (AT1R) and xanthine oxidase (XO) generates reactive oxygen species (ROS), that causes cardiac dysfunction after myocardial infarction (MI). However, it remains unknown whether its inhibition could restore the cardiac function after MI. In the present study, we examined effects of irbesartan and topiroxostat on cardiac function after MI. Methods and results：We studied blood pressure and cardiac function in a rat myocardial infraction model using tail cuff system and echocardiography. Irbesartan and topiroxostat as well as vehicle were orally administered for 35 days to rats 7 days before MI induction. Neither irbesartan nor topiroxostat altered mean blood pressure and heart rate after MI. Treatment with either drugs significantly improved cardiac function after MI. The potency of topiroxostat to restore the cardiac function was approximately half of that of irbesartan. Conclusions：A non-purine XO inhibitor, topiroxostat improved cardiac function after MI, suggesting that like irbesartan, topiroxostat may be a promising drug to treat congestive heart failure after MI.